Fluid Mechanics MCQ Questions & Answers

Fluid Mechanics MCQs : This section focuses on the "Fluid Mechanics". These Multiple Choice Questions (MCQs) should be practiced to improve the Fluid Mechanics skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

Question 1

__________ pumps are axial flow pumps.

A. Turbine
B. Propeller
C. Diffuser
D. none of these

Question 2

A Bingham fluid of viscosity μ = 10 Pa.s and yield stress, τ0 = 10 KPa, is shared between flat parallel plates separated by a distance of 10-3 m. The top plate is moving with a velocity of 1 m/s. The shear stress on the plate is

A. 10 KPa
B. 20 KPa
C. 30 KPa
D. 40 KPa

Question 3

A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke's law. A particle B with diameter 20 microns settling in the same oil will have a settling velocity

A. same as that of A.
B. one fourth as that of A.
C. twice as that of A.
D. four times as that of A.

Question 4

All pipes of a particular nominal size have the same

A. inside diameter
B. outside diameter
C. thickness
D. none of these

Question 5

At high Reynolds number

A. inertial forces control and viscous forces are unimportant.
B. viscous forces predominate.
C. inertial forces are unimportant and viscous forces control.
D. none of these.

Question 6

Brownian movement is prominent in the particle size range of __________ microns in case of settling of a particle in a fluid.

A. 2 to 3
B. 0.01 to 0.10
C. 200 to 300
D. 100 to 1000

Question 7

Co-efficient of velocity is __________ the coefficient of discharge.

A. less than
B. more than
C. equal to
D. not related to

Question 8

Dimension of absolute viscosity is

A. ML-1T-1
B. MLT-1
C. ML-1T
D. MLT

Question 9

Dimension of surface tension is(where, F = force, L = length)

A. FL-1
B. F-1 . L
C. F.L-2
D. F-2 . L

Question 10

Foot valves provided in pumps are __________ valves.

A. relief
B. three/four way
C. pressure reducing
D. directional control

Question 11

For a particle settling in water at its terminal settling velocity, which of the following is true ?

A. Buoyancy = weight + drag
B. Weight = buoyancy + drag
C. Drag = buoyancy + weight
D. Drag = weight

Question 12

For Laminar flow through a packed bed, the pressure drop is proportional to (Vs is the superficial liquid velocity and Dp is the particle diameter)

A. Vs/Dp2
B. Vs2/Dp2
C. Vs2/Dp3
D. Vs/Dp3

Question 13

For the transfer of solution of thick slurry, the pump used is a __________ pump.

A. reciprocating
B. gear
C. diaphragm
D. centrifugal

Question 14

Head developed by a centrifugal pump depends on its

A. speed
B. impeller diameter
C. both (a) and (b)
D. neither (a) nor (b)

Question 15

Hydraulic mean depth (Dm) for a circular pipe of diameter 'D' flowing full is 0.25 D. For a circular channel, at Dm = 0.3 D, gives the condition for the maximum

A. flow rate
B. mean velocity
C. both 'a' & 'b'
D. neither 'a' nor 'b'

Question 16

If the discharge of a centrifugal pump is throttled, then its suction lift

A. increases
B. decreases
C. remains unchanged
D. data insufficient to predict

Question 17

In case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, whereas for a hydraulically rough pipe, the resistance to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equal values of

A. relative roughness.
B. absolute roughness.
C. friction co-efficient for flows at equal Reynold number.
D. all (a), (b) & (c).

Question 18

In fluid flow, cavitation is caused, if the

A. fluid velocity decreases to zero.
B. total energy decreases.
C. both (a) and (b).
D. flow pressure approaches its vapor pressure at the prevailing temperature.

Question 19

Laminar flow of a Newtonion fluid ceases to exist, when the Reynolds number exceeds

A. 4000
B. 2100
C. 1500
D. 3000

Question 20

Maximum theoretical suction lift for water at 15°C by a centrifugal pump is 34 ft. The same for water at 90°C will be __________ ft.

A. 40
B. 34
C. 8
D. 37

Question 21

Molten soap mass is transported by a __________ pump.

A. diaphragm
B. reciprocating
C. gear
D. centrifugal

Question 22

Most commonly used joint in the underground pipe lines is the

A. sleevejoint
B. coupling
C. flange
D. expansion joint

Question 23

Nominal size of the discharge pipe of a pump is usually __________ the nominal size of the inlet pipe.

A. smaller than
B. larger than
C. same as
D. twice

Question 24

Pick out the correct statement.

A. A forced vortex occurs when fluid rotates as a solid about an axis.
B. In laminar flow, Newton's law of viscosity does not apply.
C. A free vortex occurs, when fluidrotates as a solid.
D. In turbulent flow, there are neither cross-currents nor eddies.

Question 25

Pick out the wrong statement.

A. Momentum transfer in laminar flow results from veclocity gradient.
B. A fluid in equilibrium is not free from shear stress.
C. The viscosity of a non-Newtonion fluid is a function of temperature only.
D. both (b) and (c)

Question 26

Power loss in an orificemeter is __________ that in a venturimeter.

A. less than
B. same as
C. more than
D. data insufficient, cannot be predicted

Question 27

Pressure drag does not depend upon the

A. roughness of surface of the body.
B. pressure of main flow only.
C. length of the body in flow direction.
D. all (a), (b) and (c)

Question 28

Schedule number of a pipe, which is a measure of its wall thickness, is given by

A. 1000 P'/S
B. 100 P'/S
C. 1000 S/P'
D. 10000 P'/S

Question 29

Shear stress in a fluid flowing in a round pipe

A. varies parabolically across the cross-section.
B. remains constant over the cross-section.
C. is zero at the centre and varies linearly with the radius.
D. is zero at the wall and increases linearly to the centre.

Question 30

The dimension of dynamic viscosity is

A. ML-1T-1
B. L2T-1
C. LT-2
D. ML-1T-2

Question 31

The drag co-efficient for a bacterium moving in water at 1 mm/s, will be of the following order of magnitude (assume size of the bacterium to be 1 micron and kinematic viscosity of water to be 10-6m2/s).

A. 24000
B. 24
C. 0.24
D. 0.44

Question 32

The fluid in which the shearing stress within it is proportional to the velocity gradient across the sheared section, is called a __________ fluid.

A. Bingham
B. Newtonion
C. perfect
D. none of these

Question 33

The fluid property, due to which, mercury does not wet the glass is

A. surface tension
B. viscosity
C. cohesion

Question 34

The head loss in turbulent flow in a pipe varies

A. as velocity
B. as (velocity)2
C. inversely as the square of diameter
D. inversely as the velocity

Question 35

The maximum delivery pressure of compressors can be upto __________ atmospheres.

A. 10
B. 100
C. 250
D. 1000

Question 36

The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the

A. discharge.
B. suction.
C. suction minus vapor pressure of the liquid at suction temperature.
D. discharge minus vapor pressure of the liquid at the discharge temperature.

Question 37

The normal stress is the same in all directions at a point in a fluid, when the fluid is

A. non-viscous.
B. incompressible.
C. both (a) and (b).
D. having no motion of one fluid layer relative to the other.

Question 38

The pitot static tube does not measure the __________ pressure.

A. static
B. total
C. difference in static & dynamic
D. all (a), (b) and (c)

Question 39

The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is

A. 0.5
B. 1
C. 1.5
D. 2

Question 40

The resistance wire used in a hot wire anemometer for conducting electrical current is made of

A. copper
B. tungsten
C. chromium
D. aluminium

Question 41

The terminal velocity of a particle moving through a fluid varies as dpn. What is the value of n' for Newton's law regime ?

A. 0.5
B. 1
C. 1.5
D. 3

Question 42

The terminal velocity of a small sphere settling in a viscous fluid varies as the

A. first power of its dimeter.
B. inverse of the fluid viscosity.
C. inverse square of the diameter.
D. square of the difference in specific weights of solid & fluid.

Question 43

The velocity profile for turbulent flow through a closed conduit is

A. logarithmic
B. parabolic
C. hyperbolic
D. linear

Question 44

Water hammer in a pipeline results from the

A. bursting of pipelines due to closure by a valve.
B. rapid pressure change due to a rapid change in the rate of flow.
C. pressure increase due to closure of a valve resulting in decrease in rate of flow.
D. none of these.

Question 45

What is the normal range of exit cone angle of a venturimeter ?

A. 2 to 5
B. 7 to 15
C. 15 to 25
D. >25

Question 46

When the momentum of one fluid is used for moving another fluid, such a device is called a/an

A. jet pump
B. blower
C. acid egg
D. none of these

Question 47

Which of the following denotes the effect of compressibility in fluid flow ?

A. Weber number
B. Mach number
C. Euler number
D. Reynolds number

Question 48

Which of the following is not a dimension-less parameter ?

A. Euler number
B. Specific gravity
C. Fanning friction factor
D. None of these

Question 49

Which of the following is not concerned with the fluid-particle interaction ?

A. Drag co-efficient
B. Froude number
C. Galileo number
D. Weber number

Question 50

With increasing flow rate, the hydraulic efficiency of a centrifugal pump

A. monotonically decreases.
B. decreases and then increases.
C. remains constant.
D. increases and then decreases.

Question 51

_____ is a mechanical gadget used to prevent leaks.

A. Hydrogen fitting
B. Stuffing Box
C. Mechanical Box
D. None of the mentioned

Question 52

Drain pipes are present to remove _____

A. Waste
B. Urea
C. Condensate
D. None of the mentioned

Question 53

In a rota meter _________ force is directly proportional to _____ of the fluid.

A. Buoyancy, Linear Velocity
B. Gravitational, Volumetric flow rate
C. Gravitational, Linear Velocity
D. Buoyancy, Volumetric flow rate

Question 54

In Bernoulli's equation, the friction correction factor is added to the LHS and the energy contributed by the pump is written on the RHS.

A. TRUE
B. FALSE

Question 55

In food industry, chlorine line is painted _____ and hydrogen line is painted _____

A. Yellow, black
B. Green, blue
C. Orange, red
D. Yellow, red

Question 56

Pipes are described in the form of _____

A. None of the mentioned
B. Formation Number
C. All of the mentioned
D. Schedule Number

Question 57

Statement 1: Diaphragm pumps can handle corrosive material and do not have leakage problems, but, they only vibrate hence the output is low.

A. True, negative displacement pump
B. True, positive displacement pump
C. False, negative displacement pump
D. False, positive displacement pump

Question 58

Statement 1: Reynolds number is the ratio of viscous force to Inertial Force.

A. True, False
B. True, True
C. False, False
D. False, True

Question 59

The energy loss due to the friction at the walls of a pipe is called _____

A. Kinetic friction
B. Skin friction
C. Static friction
D. None of the mentioned

Question 60

What is Kinetic Energy Factor in the Bernoulli's equation?

A. It is because friction varies
B. It is because friction stays constant
C. It is because the velocity in every layer varies and only the average velocity is accounted hence a correction factor is a need
D. None of the mentioned

Question 61

Which correction of the orifice meter is corrected in the venturimeter?

A. The eddies are not formed as the entrance to the downstream is not very big as compared to the vena contracta
B. The throat diameter can be changed
C. All of the mentioned
D. None of the mentioned

Question 62

Which of the following is true about Centrifugal pumps?

A. It's suitable for corrosive and toxic fluids
B. It has a high pressure head
C. Priming is not needed
D. None of the mentioned

Question 63

Which of the following is true about On-Off Control?

A. On-Off valves are called Plug Cocks
B. The size of the valve path is as big as the pipe itself
C. Pressure drop in these is the least compared to all other valves
D. All of the mentioned

Question 64

Which of the following is true about Rotary pumps?

A. These consist of gear pumps which create high pressures
B. In internal gear pumps, a pinion gear is driven by a motor which is eccentric and the ring gear is co-axial and is driven by the pinion gear
C. In Spur gears, vacuum created allows liquid to flow from suction to delivery line
D. All of the mentioned

Question 65

Which of the following is untrue about non-return valves?

A. They're also called foot valves as they're present at the foot of centrifugal pumps to prevent priming
B. They prevent flow in the opposite direction even if the pressure increases in the opposite direction
C. All of the mentioned
D. None of the mentioned

Question 66

Which of the following pumps is this pump- It has no rotating or reciprocating parts involved. No leakage. Air/gas used to impart energy.

A. Piston pump
B. Diaphragm pump
C. Gear pump
D. Air-lift pump

Question 67

A small shear force is applied on an element and then removed. If the element regains it’s original position, what kind of an element can it be?

A. Solid
B. Liquid
C. Fluid
D. Gaseous

Question 68

Velocity of liquid hydrocarbon fuels in a pipeline can not be measured by magnetic flowmeters, because their __________ is very low/small.

A. Thermal conductivity
B. Electrical conductivity
C. Specific gravity
D. Electrical resistivity

Question 69

For turbulent fluid flow in pipe, the expression for Prandtl one seventh power law is (where, r = pipe radius, x = distance).

A. V/Vmax = (x/r)1/7
B. V/Vmax = (r/x)1/7
C. V/Vmax = (x.r)1/7
D. None of these

Question 70

Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, σ = surface tension of mercury)

A. D
B. 1/d
C. Σ
D. L/σ

Question 71

What is the force required (in Newtons) to hold a spherical balloon stationary in water at a depth of H from the air-water iterface? The balloon is of radius 0.1 m and is filled with air.

A. 4πg/3
B. 0.01πgH/4
C. 0.01πgH/8
D. 0.04πgH/3

Question 72

With increase in molecular weight of the gas, the head developed by a centrifugal compressor will

A. Decrease
B. Increase
C. Remain same
D. Unpredictable

Question 73

Priming of a centrifugal pump is done to

A. Increase the mass flow rate of fluid
B. Develop effective pressure rise by the pump
C. Avoid chances of separation inside the impeller
D. None of these

Question 74

Pressure drop (Δp) for a fluid flowing in turbulent flow through a pipe is a function of velocity (V) as

A. V1.8
B. V-0.2
C. V2.7
D. V2

Question 75

__________ pump is the most suitable device for discharging a liquid against a pressure of ≥ 1500 kgf/cm².

A. Centrifugal
B. Piston
C. Plunger
D. Vane

Question 76

Pressure drop in a fluidised bed reactor is __________ that in a similar packed bed reactor.

A. Less than
B. More than
C. Same as
D. None of these

Question 77

The terminal velocity of a small sphere settling in a viscous fluid varies as the

A. First power of its dimeter
B. Inverse of the fluid viscosity
C. Inverse square of the diameter
D. Square of the difference in specific weights of solid & fluid

Question 78

Curve III in the above diagram represents a/an

A. Dilatent fluid
B. Pseudo plastic fluid
C. Ideal plastic
D. None of these

Question 79

A hydraulic ram acts as a/an __________ pump.

A. Centrifugal
B. Reciprocating
C. Impulse
D. Parallel cylinder

Question 80

The capacity of an accumulator is the maximum

A. Energy which it can store
B. Discharge which it can deliver
C. Liquid which it can store
D. None of these

Question 81

The inherent characteristic of an equal percentage valve relating flow rate 'q' with valve stem movement 'x' are described by the equation

A. dq/dx = K
B. dq/dx = K.q
C. dq/dx = K/q
D. dq/dx = Kq²

Question 82

What is the value of Fanning friction factor f ' for smooth pipe at NRe = 10⁶ approximately?

A. 0.003
B. 0.01
C. 0.1
D. 0.3

Question 83

For an unstable equilibrium of a floating body (where, M = metacentre.)

A. M is above G
B. M is below G
C. M & G coincide
D. None of these

Question 84

Drag force acting on a body does not depend upon the

A. Density of the fluid
B. Density of the body
C. Velocity of the body
D. Projected area of the body

Question 85

For an incompressible fluid, the bulk modulus of elasticity is

A. 5 kg/m³
B. ∞ N/m²
C. 1 N
D. 0 N/m

Question 86

Very small pressure difference (< 5 mm water coloumn) can be most conveniently measured by a/an __________ manometer.

A. U-tube water
B. U-tube mercury
C. Inclined tube mercury
D. Inclined tube water

Question 87

A fluid which has a linear relationship between the magnitude of applied shear-stress and the resulting rate of deformation is called a/an __________ fluid.

A. Newtonion
B. Non-Newtonion
C. Ideal
D. Incompressible

Question 88

The length of the tube necessary for the boundary layer to reach the centre of the tube and for fully developed flow to be established is called the __________ length.

A. Equivalent
B. Transition
C. Prandtl mixing
D. None of these

Question 89

The ratio of inertial forces to elastic forces is called the __________ number.

A. Reynolds
B. Mach
C. Euler
D. Weber

Question 90

N²Re/NFr is called the __________ number.

A. Brinkman
B. Galileo
C. Archimedes
D. Euler

Question 91

The ratio of inertial forces to gravity forces is called the __________ number.

A. Mach
B. Froude
C. Euler
D. Weber

Question 92

The ratio of pressure forces to inertial forces is called the __________ number.

A. Froude
B. Euler
C. Reynold
D. Mach

Question 93

Ratio of inertial forces to surface tension forces is called the __________ number.

A. Euler
B. Froude
C. Mach
D. Weber

Question 94

The ratio of inertial forces to viscous forces is called the __________ number.

A. Weber
B. Mach
C. Froude
D. Reynold

Question 95

Cavitation in a centrifugal pump can be avoided by keeping the

A. Inlet pressure high
B. Outlet pressure low
C. Inlet pressure low
D. Outlet pressure high

Question 96

Which of the following must be followed by the flow of a fluid (real or ideal)? (I) Newton's law of viscosity.(II) Newton's second law of motion. (III) The continuity equation.(IV) Velocity of boundary layer must be zero relative to boundary.(V) Fluid cannot penetrate a boundary.

A. I, II, III
B. II, III, V
C. I, II, V
D. II, IV, V

Question 97

Cavitation in a centrifugal pump results from

A. High discharge pressure
B. Low barometric pressure
C. High discharge velocity
D. High discharge rate

Question 98

Reciprocating pumps compared to centrifugal pumps

A. Deliver liquid at uniform pressure
B. Can handle slurries more efficiently
C. Are not subject to air binding
D. Can be operated with delivery valve closed

Question 99

Mass velocity in case of steady flow and through a constant cross-section conduit is independent of the

A. Temperature
B. Pressure
C. Both A & B
D. Neither A nor B

Question 100

For pipes that must be broken at intervals for maintenance, the connector used should be a/an

A. Union
B. Tee
C. Reducer
D. Elbow

Question 101

With the increase in depth, the hydrostatic pressure in an unaccelerated incompressible fluid (in a constant gravitational field)

A. Decreases
B. Increases linearly
C. Increases exponentially
D. Remains constant

Question 102

Water flow rate in a pipe of 3.5 metres diameter can be most economically and conveniently measured by a/an

A. Pitot tube
B. Venturimeter
C. Orificemeter
D. Rotameter

Question 103

While starting an axial flow pump, its delivery valve should be kept

A. Open
B. Closed
C. Either open or closed
D. None of these

Question 104

Pressure drag does not depend upon the

A. Roughness of surface of the body
B. Pressure of main flow only
C. Length of the body in flow direction
D. All of the above

Question 105

The equivalent diameter for pressure drop calculation for a duct of square cross-section is given by(where, x = each side of the square duct)

A. x
B. πx
C. 2x
D. x/2

Question 106

Which of the following is the most common pump for pumping either raw sewage or sludge?

A. Electromagnetic pump
B. Centrifugal pump
C. Reciprocating pump
D. Gear pump

Question 107

Liquid delivery by centrifugal pump starts, only when the head developed by it is equal to the __________ head.

A. Manometric
B. Total
C. Static
D. Friction

Question 108

The Mach number for hypersonic flow of compressible fluid is

A. 1
B. > 1
C. > 4
D. < 2

Question 109

Which of the following is used for very accurate measurement of flow of gas at low velocity?

A. Pitot tube
B. Rotameter
C. Segmental orificemeter
D. Hot wire annemometer

Question 110

For laminar flow through a closed conduit

A. Vmax = 2Vav
B. Vmax = Vav
C. Vmax = 1.5Vav
D. Vmax = 0.5Vav

Question 111

Shear stress in a fluid flowing in a round pipe

A. Varies parabolically across the cross-section
B. Remains constant over the cross-section
C. Is zero at the centre and varies linearly with the radius
D. Is zero at the wall and increases linearly to the centre

Question 112

Select the wrong statement pertaining to flow of an incompressible fluid through a venturimeter.

A. For frictionless flow, the fluid pressure entering the venturi meter will be exactly equal to that leaving the venturimeter
B. Discharge of fluid through a venturimeter depends upon the gage difference irrespective of the orientation of venturimeter
C. Venturimeter occupies less space than an orificemeter
D. Venturimeter incurs less power loss compared to an equivalent orificemeter

Question 113

Two fluids are flowing through two similar pipes of the same diameter. The Reynold's number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the first fluid, the pressure drop will

A. Increase
B. Decrease
C. Remain unchanged
D. Data insufficient to predict relative pressure drop

Question 114

A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below :Δ P/L = 375 x 10³ VOM + 10.94 x 10⁶ V²OM (SI units)If water is to be used as the fluidising medium, the minimum fluidisation velocity, VOM is

A. 12 mm/s
B. 16 mm/s
C. 24 mm/s
D. 28 mm/s

Question 115

A venturimeter can not be used for the direct measurement of

A. Datum difference in the stretch of pipeflow
B. Pressure difference in the flow throughpipeline
C. Friction loss in pipe flow
D. All of the above

Question 116

Which of the following produces maximum pressure difference for transportation of gases?

A. Vaccum pumps
B. Blowers
C. Fans
D. Compressors

Question 117

A centrifugal pump is used to pump water through a horizontal distance of 150 m, and then raised to an overhead tank 10 m above. The pipe is smooth with an I.D of 50 mm. What head (m of water) must the pump generate at its exit (E) to deliver water at a flow rate of 0.001 m³/s? The Fanning friction factor, f is 0.0062.

A. 10 m
B. 11 m
C. 12 m
D. 20 m

Question 118

The nominal size of a hose pipe is specified by its

A. I.D.
B. O.D.
C. Thickness
D. None of these

Question 119

Rise of liquid in a capillary tube is due to

A. Cohesion
C. Both A & B
D. Neither A nor B

Question 120

The normal stress is the same in all directions at a point in a fluid, when the fluid is

A. Non-viscous
B. Incompressible
C. Both A and B
D. Having no motion of one fluid layer relative to the other

Question 121

Interstage coolers are provided in a multistage compressor to

A. Save power in compressing a given volume to a given pressure
B. Cool the delivered air
C. Achieve the exact delivery pressure
D. None of these

Question 122

Purpose of relief valve in a reciprocating pump is to

A. Protect the pump against developing excessive pressure
B. Facilitate unidirectional flow of liquid
C. Reduce the discharge pressure
D. Control the rate of discharge

Question 123

Function of air vessel provided in a reciprocating pump is to

A. Reduce discharge fluctuation
B. Reduce the danger of cavitation
C. Avoid the necessity of priming
D. Increase the pump efficiency

Question 124

The speed of sound in an ideal gas varies as the

A. Temperature
B. Pressure
C. Density
D. None of these

Question 125

The energy loss in flow through ven-turimeter is less than that through flow nozzle, because in case of a flow nozzle, the

A. Length is shorter
B. Throat diameter is more
C. Sudden expansion of flow in the downstream occurs
D. Distance between the throat and the inlet is more

Question 126

Velocity at a certain point in case of streamline flow is

A. Constant
B. Independent of time
C. Both A & B
D. Neither A nor B

Question 127

Bed pressure drop in an air fluidised bed of catalyst particles (ρp = 200 kg/m³, Dp = 0.05 cm) of 60 cm bed depth and bed porosity of 0.5 expressed in cm of water (manometer) is

A. 90
B. 60
C. 45
D. 30

Question 128

In which type of fluid flow, the velocity of flow of fluid changes from point to point in the fluid at any instant?

A. Rotational
C. Turbulent
D. Non-uniform

Question 129

If the head over the triangular notch is doubled, the discharge will increase by __________ times.

A. 2
B. 2.828
C. 5.657
D. 4

Question 130

Which of the following pipe bends will incur the largest head loss ?

A. U-bend
B. 30° bend
C. 45° bend
D. 90° bend

Question 131

The distance between metacentre and __________ is called metacentric height.

A. Water surface
B. Centre of gravity
C. Centre of buoyancy
D. None of these

Question 132

The __________ pressure is measured by a static tube.

A. Dynamic
B. Static
C. Total
D. None of these

Question 133

Boiler feed water pump is usually a __________ pump.

A. Reciprocating
B. Gear
C. Multistage centrifugal
D. Diaphragm

Question 134

Applying a pressure drop across a capillary results in a volumetric flow rate 'Q' under laminar flow conditions. The flow rate for the same pressure drop, in a capillary of the same length but half the radius is

A. Q/2
B. Q/4
C. Q/8
D. Q/16

Question 135

Foot valves are provided in the suction line of a centrifugal pump to

A. Avoid priming, every time we start the pump
B. Remove the contaminant present in the liquid
C. Minimise the fluctuation in discharge
D. Control the liquid discharge

Question 136

Pumping of a corrosive liquid is generally preferred to be done by a __________ pump, as it can be made of a variety of materials including plastics.

A. Piston
B. Gear
C. Positive displacement
D. Sump

Question 137

Lower BWG means __________ of the tube.

A. Lower thickness
B. Lower cross-section
C. Outer diameter
D. Inner diameter

Question 138

In magnetic flow meters, voltage generation is

A. Due to the motion of conducting fluid through an externally generated uniform field
B. Proportional to the fluid velocity
C. Both A and B
D. Neither A nor B

Question 139

Net positive suction head (NPSH) of a centrifugal pump must be

A. Greater than the vapour pressure of the liquid
B. Less than the vapour pressure of the liquid
C. Equal to the vapour pressure of the liquid
D. Less than barometric pressure

Question 140

In a fully turbulent flow (Re > 105) in a pipe of diameter 'd', for a constant pressure gradient, the dependence of volumetric flow rate of an incompressible fluid is

A. d
B. d2
C. d2.5
D. d4

Question 141

A pressure head of 320 metres of water in meters of CCl₄ (sp.gr = 1.6) will be

A. 100
B. 200
C. 320
D. 160

Question 142

A fluidis (μ/ρ = 0.01 cm²/sec) moving at critical flow condition (NRe = 2100) through a pipe of dia 3 cms. Velocity of flow is __________ cm/sec.

A. 7
B. 700
C. 7000
D. 630

Question 143

Drag co-efficient for flow past immersed body is the ratio of __________ to the product of velocity head and density.

A. Shear stress
B. Shear force
C. Average drag per unit projected area
D. None of these

Question 144

The co-efficient of discharge of an orificemeter is a function of

A. Reynolds number at the orifice
B. Ratio of orifice dia to pipe dia
C. Both A and B
D. None of the above parameters, and has a constant value of 0.61

Question 145

Maintenance cost of a __________ pump for a particular duty is the least.

A. Centrifugal
B. Reciprocating
C. Volute
D. Gear

Question 146

Vena-contracta pressure tapping is at a distance __________ from the position of an orificemeter fitted in a pipe of internal diameter 'd'

A. D
B. 0.5d
C. 2d
D. 4d

Question 147

I.D. of 1/4" schedule 40 pipe is 0.364". I.D. of a 1/2" schedule 40 pipe would be __________ inch

A. 4.728
B. 0.5
C. 0.622
D. 0.474

Question 148

The valve commonly used in pipes larger than 2" dia is a

A. Globe valve
B. Plug-cock
C. Gate valve
D. Check valve

Question 149

If in a flow field, between any two points, then the flow must be

C. Steady, compressible and along a streamline

Question 150

Which of the following factors does not contribute to the pressure drop in a pipeline ?

A. Velocity of fluid
B. Size of pipe
C. Length of pipe and number of bends
D. None of these

Question 151

A piezometer provided in the pipe measures

A. Friction factor
B. Static pressure
C. Dynamic pressure
D. None of these

Question 152

Air vessel of a reciprocating pump is initially filled with

A. Atmospheric air
B. Compressed air
C. Water
D. None of these

Question 153

The hydraulic diameter of an annulus of inner and outer radii Ri and Ro respectively is

A. 4(Ro-Ri)
B. √(Ro-Ri)
C. 2(Ro-Ri)
D. Ro + Ri

Question 154

A centrifugal pump loses prime after starting. The reason of this trouble may be

A. Incomplete priming
B. Too high a suction lift
C. Low available NPSH and air leaks in the suction pipe
D. All of the above

Question 155

For a specific centrifugal air blower operating at constant speed & capacity, the power requirement and pressure vary

A. Directly as square of gas density
B. Directly as gas density
C. Directly as square root of gas density
D. Inversely as gas density

Question 156

The range of a particular rotameter can be increased by

A. Use of floats of different densities
B. No means
C. Increasing the diameter of the float
D. Decreasing the diameter of the float

Question 157

Two liquids manometer is used for measuring small pressure differences in

A. Liquids
B. Gases
C. Mixture of hydrocarbons
D. None of these

Question 158

Pick out the wrong statement about a streamline.

A. It is always parallel to the main direction of the fluid flow
B. It is a line across which there is no flow and it is equivalent to a rigid boundary
C. Streamlines intersect at isolated point of zero velocity and infintie velocity
D. The fluid lying between any two streamlines can be considered to be in isolation and the streamline spacing varies inversely as the velocity

Question 159

When larger particles e.g., grains are subjected to fluidisation, the corresponding bed produced is termed as the __________ bed.

A. Spouted
B. Sluggish
C. Boiling
D. Teeter

Question 160

Hydraulic mean depth (Dm) for a circular pipe of diameter 'D' flowing full is 0.25 D. For a circular channel, at Dm = 0.3 D, gives the condition for the maximum

A. Flow rate
B. Mean velocity
C. Both A & B
D. Neither A nor B

Question 161

Which of the following has the minimum compressibility?

A. Water at room temperature
B. Air at room temperature
C. Oxygen at room temperature
D. Nitrogen at room temperature

Question 162

Cd for the orifice plate varies from

A. 0.58 to 0.8
B. 0.93 to 0.98
C. 0.2 to 0.3
D. 0.02 to 0.03

Question 163

Mach number is the ratio of the speed of the

A. Fluid to that of the light
B. Light to that of the fluid
C. Fluid to that of the sound
D. Sound to that of the fluid

Question 164

Which of the following valves will incur maximum pressure drop for the same discharge of water?

A. Globe valve
B. Gate valve
C. Needle valve
D. Butterfly valve

Question 165

If more than two branches of pipes are to be connected at the same point, then use a/an

A. Elbow
B. Union
C. Tee
D. None of these

Question 166

Which law is followed by the velocity distribution in the turbulent boundary layer?

A. Parabolic law
B. Linear law
C. Logarithmic law
D. None of these

Question 167

With increase in temperature, the vapor pressure of liquids

A. Increases
B. Increases linearly
C. Decreases
D. Remains constant

Question 168

Kinetic energy of fluid per unit weight represented by the velocity head is given by

A. 2v²/gc
B. v²/2gc
C. ρv²/gc
D. ρ.v²/2gc

Question 169

A bed consists of particles of density 2000 kg/m³. If the height of the bed is 1.5 metres and its porosity 0.6, the pressure drop required to fluidise the bed by air is

A. 25.61 kPa
B. 11.77 kPa
C. 14.86 kPa
D. 21.13 kPa

Question 170

Which of the following is most prone to pulsating discharge flow ?

A. Centrifugal pump
B. Reciprocating pump
C. Gear pump
D. Axial flow pump

Question 171

Fanning friction factor equation applies to the __________ fluid flow.

A. Non-isothermal condition of
B. Compressible
C. Both A and B
D. Neither A nor B

Question 172

Pascal's law is valid, only when the fluid is

A. Frictionless and at rest
B. At rest
C. At rest and when the frictionless fluid is in motion
D. None of these

Question 173

Friction factor for a hydraulically smooth pipe at NRe = 2100 is f₁. If the pipe is further smoothened (i.e., roughness is reduced), the friction factor at the same value of NRe, will

A. Increase
B. Decrease
C. Remain unchanged
D. Increase or decrease depending on the pipe material

Question 174

Two piping system are said to be equivalent, when the __________ are same.

A. Fluid flow rate & friction loss
B. Length & friction factor
C. Diameter & friction factor
D. Length & diameter

Question 175

The pressure at a point in a fluid is not the same in all directions, when the fluid is viscous and

A. Moving
B. Static
C. Cold
D. Hot

Question 176

In fluid flow, the stagnation point is defined as a point, where the __________ is zero.

A. Flow velocity
B. Pressure
C. Total energy
D. All of the above

Question 177

A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke's law. A particle B with diameter 20 microns settling in the same oil will have a settling velocity

A. Same as that of A
B. One fourth as that of A
C. Twice as that of A
D. Four times as that of A

Question 178

A rectangular surface 3' x 4', has the lower 3 edge horizontal and 6' below a free oil surface (sp. gr. 0.8). The surface inclination is 300 with the horizontal. The force on one side of the surface is(where, y = specific weight of water)

A. 39.6y
B. 48y
C. 49.2y
D. 58y

Question 179

Dimension of surface tension is(where, F = force, L = length)

A. FL⁻¹
B. F⁻¹ . L
C. F.L⁻²
D. F⁻² . L

Question 180

In fluid flow, cavitation is caused, if the

A. Fluid velocity decreases to zero
B. Total energy decreases
C. Both A and B
D. Flow pressure approaches its vapor pressure at the prevailing temperature

Question 181

Bernoulli's equation for fluid flow is derived following certain assumptions. Out of the assumptions listed below, which set of assumptions is used in derivation of Bernoulli's equation ?1. Fluid flow is frictionless & irrotational.2. Fluid flow is steady.3. Fluid flow is uniform & turbulent.4. Fluid is compressible.5. Fluid is incompressible.

A. 1, 3, 2003
B. 2, 3, 2004
C. 1, 2, 2004
D. 1, 3, 2004

Question 182

For turbulent flow of an incompressible fluid through a pipe, the flow rate Q is proportional to (Δ P)n, where ΔP is the pressure drop. The value of exponent 'n' is

A. 1
B. 0
C. < 1
D. > 1

Question 183

Sewage sludge is __________ type of non-Newtonion fluid.

A. Dilatant
B. Bingham plastic
C. Pseudo plastic
D. None of these

Question 184

Horsepower increase of a centrifugal gas compressor without altering the volumetric flow rate will __________ the gas discharge pressure.

A. Increase
B. Decrease
C. Not change
D. Exponentially decrease

Question 185

The energy loss over a length of pipeline according to Darcy-Weisbach equation for pipe flow is _________ the mean velocity of flow.

A. Directly proportional to
B. Directly proportional to square of
C. Inversely proportional to
D. Inversely proportional to square of

Question 186

A. Less power than
B. More power than
C. Same power as
D. Data insufficient to predict

Question 187

Viscosity of a liquid decreases __________ with rise in temperature.

A. Exponentially
B. Linearly
C. Logarithmically
D. None of these

Question 188

In isotropic turbulence, the __________ are equal to each other.

A. Temporal velocity components
B. Mean square of velocity fluctuations in the three co-ordinate directions
C. Root mean square of velocity fluctuations in the three co-ordinate directions
D. None of these

Question 189

Bernoulli's equation for steady, frictionless, continuous flow states that the __________ at all sections is same.

A. Total pressure
B. Total energy
D. None of these

Question 190

The exit cone angle in case of a standard venturimeter is __________ the entrance cone angle.

A. Smaller than
B. Greater than
C. Equal to
D. Either A or B

Question 191

Transition length for a turbulent fluid entering into a pipe is around __________ times the pipe diameter.

A. 5
B. 50
C. 500
D. 1000

Question 192

The maximum discharge through a circular channel takes place, when the depth of the fluid flow is __________ times the pipe diameter.

A. 0.25
B. 0.5
C. 0.66
D. 0.95

Question 193

Transition length for turbulent flow in smooth pipe is equal to __________ times the pipe diameter.

A. 0.5
B. 5
C. 50
D. 100

Question 194

The uniformity of a gas fluidised bed depends upon the __________ of the solid particles.

A. Size
B. Surface properties
C. Both A and B
D. Neither A nor B

Question 195

The terminal velocity of a particle moving through a fluid varies as dpn. The value of n is equal to __________ in Stoke's law regime.

A. 1
B. 0.5
C. 2
D. 1.5

Question 196

For the production of very high vacuum, a __________ pump is normally used.

A. Diffusion
B. Centrifugal
C. Jet ejector
D. Piston

Question 197

Drag co-efficient in hindered settling is __________ that in free settling.

A. Less than
B. Equal to
C. Not necessarily greater than
D. Always greater than

Question 198

The curve of metacentre for a floating body __________ the curve of buoyancy.

A. Is always below
B. Is the evolute of
C. Intersects at right angle
D. Is tangential to

Question 199

At a constant speed of the centrifugal pump . it __________ the impeller diameter.

A. Capacity varies directly with
B. Head varies as the square of
C. Horsepower varies as the cube of
D. All of the above

Question 200

Navier-Stokes equation is useful in the analysis of __________ fluid flow problems.

A. Non-viscous
B. Viscous
C. Turbulent
D. Rotational

Question 201

In the Newton's law range, the terminal velocity of a solid spherical particle falling through a stationary fluid mass is __________ the fluid viscosity.

A. Directly proportional to
B. Inversely proportional to
C. Inversely proportional to the square root of
D. Independent of

Question 202

For a given Reynolds number, in a hydraulically smooth pipe, further smoothening __________ the friction factor.

A. Brings about no further reduction of
B. Increases
C. Decreases
D. None of these

Question 203

Mach number is important in a fluid flow problem, when the inertia and __________ forces predominate.

A. Elastic
B. Viscous
C. Gravity
D. None of these

Question 204

In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where M = molecular weight of the gas)

A. 1/√M
B. √M
C. 1/M
D. M

Question 205

Fanning friction factor is equal to(where, fB = Blassius friction factor).

A. fB/4
B. fB/2
C. 4fB
D. 2fB

Question 206

For the free settling of a spherical particle through a fluid, the slope of, CD-log NRe , plot is

A. 1
B. -1
C. 0.5
D. -0.5

Question 207

Various efficiencies of a centrifugal pump are related as (where, ηm = mechanical efficiency ηv = volumetric efficiency. ηma = manometric efficiency ηo = overall efficiency)

A. ηma x ηm x ηv = ηo
B. ηm = ηv . ηma
C. ηma = ηm x ηv
D. ηv = ηm x ηma

Question 208

f = 16/NRe, is valid for

A. Turbulent flow
B. Laminar flow through an open channel
D. None of these

Question 209

A fluid is a substance, that

A. Has to be kept in a closed container
B. Is almost incompressible
C. Has zero shear stress
D. Flows when even a small shear is applied to it

Question 210

A fluid is the one, which

A. Cannot remain at rest under the action of shear force
B. Continuously expands till it fills any container
C. Is incompressible
D. Permanently resists distortion

Question 211

Slugging occurs in a fluidised bed, if the bed is

A. Narrow
B. Deep
C. Both A & B
D. Neither A nor B

Question 212

A gas

A. Signifies absence of density
B. Can resist shearing action
C. Is incompressible
D. Is a supercritical vapor

Question 213

A mixed flow centrifugal pump

A. Employs such an impeller, through which the flow is a combination of radial & axial flow
B. Mixes the two fluids before pumping them
C. Pumps the two fluids separately and then mixes them
D. Employs impellers in both the radial & axial directions

Question 214

A Newtonion fluid is that

A. Which follows Newton
B. Which needs a minimum shear, before it starts deforming
C. For which shear & deformation are related as T = μ ∂u/∂y
D. None of these

Question 215

With increase in the schedule number of a pipe of a particular nominal size, the

A. Wall thickness also increases
B. I.D. of the pipe decreases
C. O.D. of the pipe remains constant
D. All of the above

Question 216

A perfect gas

A. Does not satisfy PV = nRT
B. Is incompressible and has zero viscosity
C. Has constant specific heat
D. Can't develop shear stresses

Question 217

The schedule number of a pipe is an indication of its

A. Size
B. Roughness
C. Material density
D. Wall thickness

Question 218

A relief valve

A. Provides back pressure for a cylinder
C. Is a directional control valve
D. None of these

Question 219

A streamline is

A. The line connecting the mid-points of flow cross-sections
B. Defined for uniform flow only
C. Drawn normal to the velocity vector at every point
D. Always the path of a particle

Question 220

A tube is specified by its

A. Thickness only
B. Outer diameter only
C. Thickness & outer diameter both
D. Inner diameter

Question 221

The specific speed of a pump is defined as the speed of a unit of such a size, that it

A. Delivers unit discharge at unit head
B. Requires unit power for unit head
C. Delivers unit discharge at unit power
D. None of these

Question 222

Which of the following may be termed as a variable orifice flowmeter?

A. Rotameter
B. Pitot tube
C. V-notch
D. All of the above

Question 223

A venturimeter measures the

B. Pressure
C. Point velocity
D. None of these

Question 224

Potential function is applicable only for __________ flow.

A. Irrotational
B. Turbulent
D. None of these

Question 225

A floating/submerged body is always stable, if its centre of gravity

A. Lies above its centre of buoyancy
B. And centre of buoyancy coincide
C. Lies below its centre of buoyancy
D. Lies above its meta centre

Question 226

The fluid property which matters for fall-ing rain drops to acquire spherical shape is its

A. Pressure
B. Height of descend
C. Viscosity
D. Surface tension

Question 227

Pump used for the transportation of molten sodium in a fast breader reactor is a/an __________ pump.

A. Reciprocating
B. Plunger
C. Electromagnetic
D. Gear

Question 228

Which of the following quantities are computed by using the hydraulic radius for non-circular ducts?

A. Velocity and relative roughness
C. Reynold number, relative roughness and head loss
D. Reynolds number and friction factor

Question 229

The ratio of wall drag to total drag in the Stoke's law range is

A. 0.5
B. 1
C. 1-3
D. 2-3

Question 230

The most serious disadvantage of an orificemeter is that

A. It is not very accurate
B. It is very costly
C. Most of the pressure drop is not recoverable
D. It is not suitable for measuring gas flow

Question 231

For a reciprocating pump, the indicator diagram is the graph between the

A. Discharge and overall efficiency
B. Volume swept by piston for one complete revolution and the pressure in the cylinder
C. Angle swept by the crank pin at any instant and the discharge
D. None of these

Question 232

Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have

A. Very low speeds
B. Smaller discharge
C. Higher capital &maintenance cost
D. High vibrations

Question 233

Propeller type centrifugal pumps are most suitable for

A. High capacity at high heads
B. High capacity at low heads
C. Low capacity at high heads
D. Low capacity at low heads

Question 234

The pipe wall thickness is minimum for a pipe of given nominal size having schedule number

A. 160
B. 120
C. 80
D. 40

Question 235

The equivalent diameter for fluid flow through square cross section channel of side 'x', for pressure drop calculation purpose is given by

A. 4x
B. 2x
C. x
D. √x

Question 236

Which of the following two quantities when same, makes one pipe system equivalent to another pipe system?

B. Length & discharge
C. Length & diameter
D. Friction factor & diameter

Question 237

The component of acceleration resulting due to unsteady nature of flow is called __________ acceleration.

A. Normal
B. Local
C. Convective
D. Tangential

Question 238

The equation relating friction factor to Reynold number, f-0.5 = 4 loge (NRe/√f)-0.4, is called the __________ equation.

B. Von-Karman
C. Blausius
D. Colebrook

Question 239

Friction produced by the formation of wakes is called the __________ friction.

A. Disk
B. Skin
C. Form
D. None of these

Question 240

Centre of pressure of a plane surface of arbitrary shape immersed vertically in a static mass of fluid

A. Lies above the centroid of the plane surface
B. Is independent of the specific weight of the fluid
C. Is different for different fluids
D. Is at the centroid of the plane surface

Question 241

What is the co-efficient of contraction, if a fluid jet discharging from a 50 mm diameter orifice has a 40 mm diameter at its vena-contracta?

A. 0.64
B. 1.65
C. 0.32
D. 0.94

Question 242

Sewage sludge is an example of the __________ fluid.

A. Bingham plastic
B. Newtonion
C. Pseudoplastic
D. Dilatent

Question 243

Non-colloidal solution is an example of the __________ fluid.

A. Non-Newtonion
B. Newtonion
C. Dilatent
D. Pseudoplastic

Question 244

Fluid flow at increasing rate through a diverging pipe is an example of __________ flow.

Question 245

The flow of a liquid through tapering pipe at a constant rate is an example of __________ flow.

Question 246

Gradually varying fluid flow is an example of __________ flow.

Question 247

An ideal fluid is

A. Non-viscous
B. Incompressible
C. Both A & B
D. Neither A & B

Question 248

An ideal fluid is

A. Frictionless & incompressible
B. One, which obeys Newton's law of viscosity
C. Highly viscous
D. None of these

Question 249

An ideal nozzle design aims at

A. Minimising wall friction
B. Suppressing boundary layer separation
C. Both A & B
D. Neither A nor B

Question 250

Fluid resistance to shear depends upon its

A. Rate of transfer of molecular momentum
B. Cohesion
C. Both A and B
D. Neither A nor B

Question 251

Gradually varied flow in open channel is a/an __________ flow.

Question 252

The ratio of the hydraulic radius to the diameter of the channel, for maximum mean velocity of flow in a circular channel, in open channel flow is

A. 0.3
B. 0.9
C. 0.03
D. 0.66

Question 253

The frictional resistance in laminar flow does not depend on the

A. Area of surface in contact
B. Flow velocity
C. Fluid temperature
D. Pressure of flow

Question 254

Most of the centrifugal pumps used in chemical plants are usually __________ driven.

A. Steam
B. Diesel engine
C. Electric motor
D. Gas turbine

Question 255

In case of coutte flow, the fluid flow is between two large flat parallel plates with

A. Top plate moving and the bottom plate fixed
B. Bottom plate moving and the top plate fixed
C. Both the plates fixed
D. Both the plates moving

Question 256

Capacity of a rotary gear pump can be varied by

A. Changing the speed of rotation
B. Bleeding air into suction
C. Bypassing liquid from the suction or discharge line
D. All of the above

Question 257

The capillary rise of mercury is maximum in glass tube of dia __________ mm.

A. 0.5
B. 1
C. 2
D. 5

Question 258

The pitot static tube does not measure the __________ pressure.

A. Static
B. Total
C. Difference in static & dynamic
D. All of the above

Question 259

Manometers measure the __________ pressure.

A. Vacuum as well as the atmospheric
B. Difference in
C. Absolute
D. Gage

Question 260

At high Reynolds number

A. Inertial forces control and viscous forces are unimportant
B. Viscous forces predominate
C. Inertial forces are unimportant and viscous forces control
D. None of these

Question 261

At low Reynolds number

A. Viscous forces are unimportant
B. Viscous forces control
C. Viscous forces control and inertial forces are unimportant
D. Gravity forces control

Question 262

Viscosity of water is about __________ times that of air at room temperature.

A. 15
B. 55
C. 155
D. 1050

Question 263

The most important factor, which determines the maximum height to which water can be lifted by a pump at standard temperature is the

A. Barometric pressure
B. Speed of the impeller
C. Diameter of the impeller
D. Both B and C

Question 264

Euler's equation of motion states, that at every point, the

A. Fluid momentum is constant
B. Force per unit mass equals acceleration
C. Rate of mass outflow is equal to the rate of mass inflow
D. None of these

Question 265

The buoyant force acting on a floating body is dependent on the

A. Viscosity of the liquid
B. Weight of the liquid displaced
C. Depth of immersion of the body
D. Surface tension of the liquid

Question 266

A hydraulic accumulator comprises of

A. A storage device and a control valve
B. A cylinder and a plunger
C. Two pistons and two cylinders
D. A storage tank and a ram pump

Question 267

It is possible to integrate an automatic flow controller to a

A. Flow nozzle
B. Venturimeter
C. Rotameter
D. None of these

Question 268

The maximum delivery pressure of a reciprocating compressor may be about __________ kg/cm².

A. 1000
B. 2000
C. 3000
D. 4000

Question 269

Which of the following equations as suggested by Colebrook and White gives the increase in roughness of a new surface (ε0) with age/time (t) (where, ε = roughness of the surface after time't'. α = a co-efficient to be experimentally determined)?

A. ε = ε0 + α.t
B. ε = ε0 + α.t²
C. ε = ε0 + α.t³
D. ε = ε0 + α.t⁴

Question 270

The capacity of a centrifugal pump Can be increased by increasing the

A. Impeller diameter or speed
B. Number of pumps and joining them in series
C. Number of pumps and joining them in parallel
D. All of the above

Question 271

The Reynolds number for an ideal fluid flow is

A. 4
B. 2100-4000
C. 4000
D. ∞

Question 272

What type of motion the fluid element undergoes, when it changes from one position to another position, such that the angle between the two sides change?

A. Rotation
B. Translation
C. Linear deformation
D. Angular deformation

Question 273

Pascal law is not applicable for a/an __________ fluid.

A. Accelerating frictionless
B. Static
C. Uniformly moving
D. None of these

Question 274

A globe valve is the most suitable for applications, in which

A. Fluid flow control is required
B. Fluid contains dispersed solid particles
C. Valve is required to be either fully open or fully closed
D. One way flow is required

Question 275

Fanning equation is given by ∆p/ρ = 4f. L/D . v²/2g<.sub>c . It is applicable to __________ region flow.

A. Transition
B. Laminar
C. Turbulent
D. Both B and C

Question 276

Boundary layer exists in flow

A. Of real fluids
B. Over flat surfaces only
C. In pipes only
D. Of ideal fluids only

Question 277

Buoyant force

A. For non-symmetrical bodies is not vertical
B. Depends on the depth of the submergence of the floating body
C. Depends on the weight of the floating body
D. None of these

Question 278

The line of action of the buoyant force acts through the

A. Centroid of the displaced volume of fluid
B. Centre of gravity of a submerged body
C. Centroid of the volume of any floating body
D. None of these

Question 279

In a dry packed bed, the pressure drop will be changed by increasing the flow rate as

A. V1.8
B. V-0.8
C. V
D. V-1

Question 280

Identification of pipelines carrying different liquids and gases is done by the __________ of the pipe.

A. Diameter
B. Colour
C. Altitude
D. None of these

Question 281

An isentropic process is the one, in which

A. pv = constant
B. pvr = constant
C. pvr = constant, and process is reversible
D. None of these

Question 282

Actual lift of a pump is always less than the theoretical lift and is limited by the

A. Specific gravity & temperature of the liquid
B. Leakage & pressure decreasing at higher elevations
C. Frictional resistance through pipes, fittings & passages
D. All of the above

Question 283

Which of the following can be used to create a flow of gas, where no significant compression is required?

A. Reciprocating compressor
B. Blower
C. Axial flow compressor
D. Centrifugal compressor

Question 284

For motion of spherical particles in a stationary fluid, the drag co-efficient in hindered settling compared to that in free settling is

A. More
B. Less
C. Equal
D. More or less, depending on the type of particle

Question 285

Choking in case of pipe flow means that a

A. Specified mass flow rate can not be achieved
B. Valve is closed in the line
C. Restriction in flow cross-section area occurs
D. None of these

Question 286

Cavitation can be prevented by

A. Suitably designing the pump
B. Maintaining the suction head sufficiently greater than the vapour pressure
D. Maintaining suction head lower than the vapour pressure

Question 287

The contraction co-efficient for Borda's mouthpiece (for frictionless fluid) is

A. 0.1
B. 0.5
C. 0.94
D. 1

Question 288

In case of venturimeters, friction losses are about __________ percent of maximum velocity head.

A. 2
B. 8
C. 12
D. 20

Question 289

Erosion and pits formation on the impeller of a centrifugal pump may be due to

A. Cavitation
B. Low speed of impeller
C. Its operation with delivery valve closed for considerable time after starting the pump
D. Off centering of pump with motor

Question 290

Check in a centrifugal pump is

A. Provided in the discharge line
B. Generally a globe valve
C. Provided to prevent liquid from backing up through the pump when the pump is turned off or accidently stops running
D. All of the above

Question 291

Check valves are used

A. At high pressure
B. In bends
C. For controlling water flow
D. For unidirectional flow

Question 292

Nominal Pipe Size (NPS) of a pipe less than 12 inches in diameter indicates its

A. Inner diameter
B. Outer diameter
C. Thickness
D. Neither inner nor outer diameter

Question 293

Experimental study of laminar fluid flow through a circular tube was conducted by

A. Reynolds
B. Hagen and Poiseuille
C. Pascal
D. Blake-Plummer

Question 294

Centrifugal pump is normally classified on the basis of the

A. Rpm
B. Type of casing
D. Number of blades in impeller

Question 295

The ratio of the wall drag to the form drag in the Stoke's law range (for motion of spherical particles in a stationary fluid) is

A. 0.5
B. 1
C. 2
D. 0.33

Question 296

Cocks are used to control

A. Water
B. Any liquid
C. Solids
D. None of these

Question 297

The fluid jet discharging from a 2" diameter orifice has a diameter of 1.75" at its vena-contracta. The co-efficient of contraction is

A. 1.3
B. 0.766
C. 0.87
D. None of these

Question 298

What is the normal range of exit cone angle of a venturimeter?

A. 2 to 5
B. 7 to 15
C. 15 to 25
D. >25

Question 299

Upto what value of 'Mach number', a fluid may be considered as incompressible?

A. 0.03
B. 0.3
C. 3
D. 10

Question 300

The head loss due to sudden contraction is proportional to

A. Velocity
C. Turbulence
D. None of these

Question 301

Boundary layer separation is characterised by one of the conditions given below, where 'Re' is the Reynolds number for the flow. Select the appropriate conditions.

A. Re << 1, accelerating flow
B. Re >> 1, accelerating flow
C. Re << 1, decelerating flow
D. Re >>1, decelerating flow

Question 302

For the same terminal conditions and fitting size, the least friction loss is incurred in a/an

A. T-joint
B. Union
C. 45° elbow
D. 90°bend

Question 303

The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the

A. Discharge
B. Suction
C. Suction minus vapor pressure of the liquid at suction temperature
D. Discharge minus vapor pressure of the liquid at the discharge temperature

Question 304

The excess of the sum of pressure & velocity heads over the vapor pressure of the liquid at the suction is called the

A. Static submergence
B. Net positive suction head (NPSH)
C. Cavitation sensitivity
D. Priming

Question 305

The vent valve provided in a liquid handling centrifugal pump is

A. Generally a needle valve
B. Used to release any gases that might be vapour locking the pump
C. Helpful in easy removal of samples
D. All of the above

Question 306

Stoke's equation is valid in the Reynolds number range

A. 0.01 to 0.1
B. 0.1 to 2
C. 2 to 10
D. 10 to 100

Question 307

A liquid is pumped at the rate of 600 litres using 1000 rpm. If the rpm is changed to 1100, the liquid pumped is __________ litres.

A. 600
B. 660
C. 1.1
D. 60

Question 308

In case of turbulent flow of fluid through a circular pipe, the

A. Mean flow velocity is about 0.5 times the maximum velocity
B. Velocity profile becomes flatter and flatter with increasing Reynolds number
C. Point of maximum instability exists at a distance of 2r/3 from the pipe wall (r = pipe radius)
D. Skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more

Question 309

In case of laminar flow of fluid through a circular pipe, the

A. Shear stress over the cross-section is proportional to the distance from the surface of the pipe
B. Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder
C. Velocity profile varies hyperbolically and the shear stress remains constant over the cross-section
D. Average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)

Question 310

Centrifugal compressors compared to reciprocating compressors

A. Require less space
B. Have quieter operation
C. Have lower operating costs
D. All of the above

Question 311

For flow of fluids through packed bed, the superficial velocity is

A. Less than the average velocity through channels
B. More than the average velocity through channels
C. Dependent on the pressure drop across the bed
D. Same as the average velocity through channels

Question 312

Assuming flow to be laminar, if the diameter of the pipe is halved, then the pressure drop will

A. Increase
B. Decrease
C. Remain same

Question 313

Buckingham-π theorem states that in any physical problem including 'n' quantities having 'm' diamensions, the quantities can be arranged into __________ independent dimensionless parameters.

A. M
B. N
C. N-m
D. N/m

Question 314

In the laminar boundary layer flow over a flat plate, the ratio (δ/x) varies as :(where, 'δ' is the boundary layer thickness and 'x' is the distance from the leading edge in the direction of flow).

A. Re
B. √Re
C. 1/Re
D. Re-1/2

Question 315

Hydraulic radius is the ratio of

A. Wetted perimeter to flow area
B. Flow area to wetted perimeter
C. Flow area to square of wetted perimeter
D. Square root of flow area to wetted perimeter

Question 316

Prandtl number is a measure of the

A. Heat conduction to viscosity of a fluid
B. Cp/Cv of a fluid
C. Elastic force to pressure force in the fluid flow
D. Inertial force to elastic force in the fluid flow

Question 317

Mass velocity is independent of temperature & pressure, when the flow is

C. Steady and the cross-section is unchanged
D. Unsteady and the cross-section is changed

Question 318

What causes convective acceleration in fluid flow?

A. Steep slope in flow
C. Non-uniformity of flow
D. Turbulence in flow

Question 319

Normal depth in open channel flow is the depth of flow in the channel

A. Corresponding to uniform flow
B. Measured normal to the channel bed
D. None of these

Question 320

Which of the following is not concerned with the fluid-particle interaction?

A. Drag co-efficient
B. Froude number
C. Galileo number
D. Weber number

Question 321

Which of the following is dimensionless?

A. Angular velocity
B. Fanning friction factor
C. Specific volume
D. None of these

Question 322

The pressure co-efficient is the ratio of pressure forces to __________ forces.

A. Viscous
B. Inertial
C. Gravity
D. Surface tension

Question 323

Pressure co-efficient is the ratio of pressure forces to __________ forces.

A. Gravity
B. Inertial
C. Viscous
D. None of these

Question 324

The actual velocity at vena-contracta for flow through an orifice from a reservoir is given by

A. Cv . √(2gH)
B. Cc . √(2gH)
C. Cd . √(2gH)
D. Cv . Va

Question 325

If 'x' is the depth of flow in an open channel of large width, then the hydraulic radius is equal to

A. x
B. x/2
C. x/3
D. 2x/3

Question 326

In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes

A. Less than atmospheric pressure
B. More than liquid vapor pressure
C. Less than liquid vapor pressure
D. More than atmospheric pressure

Question 327

A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump.

A. Sump
B. Volute
C. Vacuum
D. Submerged

Question 328

Check valve is used for __________ flow.

A. Very precise control of
B. Unidirectional
C. Multidirectional
D. None of these

Question 329

A rotameter works on the principle of __________ pressure drop.

A. Constant
B. Variable
C. Both A & B
D. Neither A nor B

Question 330

The continuity equation of fluid mechanics utilises the principle of conservation of

A. Momentum
B. Mass
C. Energy
D. Both B & C

Question 331

Which of the fluid forces are not considered in the Reynold's equation of flow?

A. Viscous forces
B. Turbulent forces
C. Pressure forces
D. Compressibility forces

Question 332

A Bingham fluid of viscosity μ = 10 Pa.s and yield stress, τ₀ = 10 KPa, is shared between flat parallel plates separated by a distance of 10⁻³ m. The top plate is moving with a velocity of 1 m/s. The shear stress on the plate is

A. 10 KPa
B. 20 KPa
C. 30 KPa
D. 40 KPa

Question 333

A. Elevation & kinetic energy
B. Elevation & pressure
C. Kinetic energy & pressure
D. None of these

Question 334

The phenomenon occuring during pumping of a liquid solution containing dissolved gases, which may come out of the solution giving rise to gas pockets, is termed as

A. Evaporation
B. Cavitation
C. Sublimation
D. Stripping

Question 335

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpmHead = 8 metresFlow = 1000 litres/minutes.If its speed is halved, then the new head will be __________ metres.

A. 2
B. 4
C. 8
D. 5.5

Question 336

A mercury (specific gravity = 13.6) manometer connected across an orificemeter fitted in a pipe shows a manometer reading of 2 cms. If the manometer liquid is changed to carbon tetrachloride (specific gravity = 1.6), then for the same flow rate of water the new manometer reading will be __________ cms.

A. 17
B. 42
C. 84
D. 1.8

Question 337

Hydrometer measures the specific gravity of liquids based on the principles of buoyancy. Pycnometer is used to measure the specific gravity of

A. Powder & grannular solids
B. Liquids
C. Low melting point semi-solids
D. All of the above

Question 338

Discharge from a 24 inch pipe of water at 10 ft/sec will be __________ ft³/sec.

A. 7.65
B. 32.36
C. 48.22
D. 125.6

Question 339

Minimum fluidisation velocity for a specific system depends upon the

A. Particle size
B. Fluid viscosity
C. Density of both the particle & the fluid
D. All of the above

Question 340

The ratio of width to depth for the most economical rectangular section in open channel flow is

A. 0.5
B. 1
C. 1.5
D. 2

Question 341

Drag is defined as the force exerted by the

A. Fluid on the solid in a direction opposite to flow
B. Fluid on the solid in the direction of flow
C. Solid on the fluid
D. None of these

Question 342

Slugging in a fluidised bed can be avoided by using

A. Tall narrow vessel
B. Deep bed of solids
C. Shallow beds of solids and proper choice of particle size
D. Very large particles

Question 343

Fluid flow through a packed bed is represented by the __________ equation.

A. Fanning's
B. Ergun's
C. Hagen-Poiseuille's
D. None of these

Question 344

Volute of a centrifugal pump should be designed in a fashion, such that the

B. Moving stream gradually reduces velocity
C. Mean velocity remains constant
D. None of these

Question 345

In hindered settling, the particles are

A. Placed farther from the wall
B. Not affected by other particles and the wall
C. Near each other
D. None of these

Question 346

The main factor on which the behaviour of a mass of fluidised solid depends mainly is the

A. Fluid characteristics
B. Particle size
C. Both A and B
D. Neither A nor B

Question 347

A Pitot tube indicates 5 cm of water (manometer) when it is being used for measuring velocity of air. The velocity of air in m/sec is

A. 5
B. 14.1
C. 56.22
D. 28.2

Question 348

For flow through an orifice from a reservoir, the actual velocity at the vena con-tracta is given by

A. √(2gh)
B. C.V. √(2gh)
C. Cd √(2gh)
D. Cc √(2gh)

Question 349

In open channel flow in a rectangular channel, the ratio between the critical depth and the initial depth, when a hydraulic jump occurs is

A. 0.5
B. 0.84
C. 1.84
D. 1.25

Question 350

Power required by a centrifugal pump is proportional to (where, D = diameter, N = r.p.m)

A. N²D³
B. ND²
C. N²D
D. N³D⁵

Question 351

The location of centre of pressure, which defines the point of application of the total pressure force on the surface, can be calculated by applying the principle of moments according to which "sum of the moment of the resultant force about an axis is equal to the sum of the components about the same axis". The centre of pressure of a rectangular surface (of width 'w') immersed vertically in a static mass of fluid is at a depth of(where, y = depth of the liquid)

A. 1/3y
B. 2y/3
C. 1/4y
D. 3y/4

Question 352

A special type of liquid transporting device is the diffuser pump, in which __________ are minimised.

A. Bearing losses
B. Disk friction
C. Shock losses
D. Cavitation

Question 353

A pipe of I.D. 4 m is bifurcated into two pipes of I.D. 2 m each. If the average velocity of water flowing through the main pipe is 5 m/sec, the average velocity through the bifurcated pipes is

A. 20 m/sec
B. 10 m/sec
C. 5√2 m/sec
D. 5 m/sec

Question 354

Weber number is the ratio of inertial force to __________ force.

A. Surface tension
B. Gravity
C. Viscous
D. Elastic

Question 355

One stoke (unit of kinematic viscosity) is equivalent to

A. 1 cm²/second
B. 1 m²/second
C. 1 gm/cm. second
D. 1 kg . m/second

Question 356

When the water is warm, the height to which it can be lifted by a pump

A. Decreases due to reduced viscosity
B. Decreases due to reduced vapour pressure
C. Increases due to increased vapour pressure
D. Decreases due to increased frictional resistance

Question 357

For a particle settling in water at its terminal settling velocity, which of the following is true?

A. Buoyancy = weight + drag
B. Weight = buoyancy + drag
C. Drag = buoyancy + weight
D. Drag = weight

Question 358

Pick out the correct statement.

A. A forced vortex occurs when fluid rotates as a solid about an axis
B. In laminar flow, Newton's law of viscosity does not apply
C. A free vortex occurs, when fluidrotates as a solid
D. In turbulent flow, there are neither cross-currents nor eddies

Question 359

Pick out the wrong statement.

A. The form drag is dependent upon the occurrence of a wake
B. The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent) varies linearly as the radial distance
C. An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity
D. Existence of the boundary layer in fluid flow is because of viscosity of the fluid

Question 360

Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f₁ and that for smooth pipe is f₂. Pick out the correct statement.

A. f₁ = f₂
B. f₁ < f₂
C. f₁ > f₂
D. Data not sufficient to relate f₁ & f₂

Question 361

In turbulent flow, a rough pipe has the same friction factor as a smooth pipe

A. In the zone of complete turbulence
B. When the roughness projections are much smaller than the thickness of the laminar film
C. Everywhere in the transition zone
D. When the friction factor is independent of the Reynold's number

Question 362

In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure __________ the vapor pressure of the liquid at the suction temperature.

A. Lower than
B. Higher than
C. Equal to
D. None of these

Question 363

Drag co-efficient for motion of spherical particles in a stationary fluid in the stoke's law range is

A. 24/NRe,p
B. 16/NRe,p
C. 64/NRe,p
D. 48/NRe,p

Question 364

Vena-contracta formed during flow of a liquid through an orificemeter has

A. Minimum liquid cross-section
B. More diameter compared to orifice diameter
C. Minimum velocity of fluid stream
D. None of these

Question 365

Hydraulic intensifier is used for increasing the

A. Rate of velocity of liquid supply
B. Rate of flow through delivery pipeline of a pump
C. Intensity of pressure of the liquid
D. Momentum rate through delivery pipe

Question 366

In case of end to end connection of two or more pipes in series, the __________ each pipe.

A. Same rate of flow passes through
B. Head loss is same through
C. Rate of flow in each pipe is proportional to the length of
D. Total flow rate is the sum of flow rate in

Question 367

For the manometer set up shown in the figure, the pressure difference PA - PB is given by

A. (ρH - ρair)gH
B. (ρH - ρL)gH
C. (ρH - ρL) gH + (ρL - ρair) . g(L - H)
D. (ρH - ρL) gL + (ρL - ρair)gH

Question 368

Pressure difference between two points in vessels, pipelines or in two different pipelines can be measured by a differential manometer. The pressure difference measured as the mm of water coloumn in case of mercury-water, differential manometer is equal to (where, H = difference in height of mercury column in mm).

A. H
B. 12.6 H
C. 13.6 H
D. 14.6 H

Question 369

The time of oscillation of a floating body is

A. Longer, if metacentric height is increased
B. Independent of the metacentric height
C. Dependent on the buoyant forces only
D. None of these

Question 370

The line traced by a single fluid particle as it moves over a period of time is called __________ line.

A. Stream
B. Path
C. Equipotential
D. None of these

Question 371

The dimension of surface tension is

A. ML⁻²
B. MT⁻²
C. MLT⁻²
D. ML⁻²T

Question 372

With a constant diameter impeller of a centrifugal pump

A. Its capacity varies directly as the square of speed
B. Head varies as the square of speed
C. Horsepower input varies as the square of speed
D. Head varies as the speed

Question 373

In a fluidised bed reactor

A. Temperature gradients are very high
B. Temperature is more or less uniform
C. Hot spots are formed
D. Segregation of the solids occurs

Question 374

In a free vortex, the

A. Velocity changes linearly with radial distance
B. Flow is necessarily rotational
C. Radial component of velocity is same everywhere
D. Stream lines are not circular

Question 375

The friction factor for turbulent flow in a hydraulically smooth pipe

A. Depends only on Reynolds number
B. Does not depend on Reynolds number
C. Depends on the roughness
D. None of these

Question 376

Water hammer in a pipeline results from the

A. Bursting of pipelines due to closure by a valve
B. Rapid pressure change due to a rapid change in the rate of flow
C. Pressure increase due to closure of a valve resulting in decrease in rate of flow
D. None of these

Question 377

Air vessel provided in a reciprocating pump is for

B. Making the friction in pipe uniform
D. None of these

Question 378

Speed of sound in an ideal gas depends on its

A. Temperature
B. Pressure
C. Specific volume
D. None of these

Question 379

Which of the following options will facilitate the achievement of a very high head (say 30 metres) in case of a centrifugal pump?

A. Increasing the impeller speed and the volute area
B. Increasing the number of vanes in the impeller
C. Mounting of two or more impellers in series on a single shaft
D. Either of A, B or C

Question 380

In continuous fluidisation

A. Solids are completely entrained
B. The pressure drop is less than that for batch fluidisation
C. There is no entrainment of solids
D. Velocity of the fluid is very small

Question 381

Pick out the wrong statement.

A. Surface tension of a liquid is because of the difference in magnitude of adhesive & cohesive forces
B. A hydrometer used for the determination of specific gravities of liquids works on the principle of buoyant forces
C. In case of unsteady fluid flow, the velocity at any given point does not change with time
D. Turbulent fluid flow is characterised by the rapid fluctuation of instantaneous pressure & velocity at a point

Question 382

In parallel pipe problems, the

A. Head loss is the same through each pipe
B. Discharge is the same through all the pipes
C. Total head loss is equal to the sum of the head losses through each pipe
D. None of these

Question 383

In turbulent flow, the

A. Fluid particles move in an orderly manner
B. Momentum transfer is on molecular scale only
C. Shear stress is caused more effectively by cohesion than momentum transfer
D. Shear stresses are generally larger than in a similar laminar flow

Question 384

The boundary layer is that part of a moving fluid, in which the fluid velocity is

A. Affected by the fluid flow pressure
B. Constant
C. Affected by the presence of a solid boundary
D. All of the above

Question 385

A centrifugal pump designed for handling water (μ = 1 cp) will deliver __________ when pumping a thicker oil (μ = 30 cp).

C. More capacity
D. Less head & more capacity

Question 386

Which of the following flow measuring devices is an area meter?

A. Venturimeter
B. Orifice meter
C. Anemometer
D. Rotameter

Question 387

For a given fluid flow rate, which of the following incurs maximum head loss?

A. Orifice meter
B. Venturimeter
C. Flow nozzle
D. All of the above

Question 388

A rotameter through which air at room temperature and atmospheric pressure is flowing gives a certain reading for a flow rate of 100 cc/sec. If helium (molecular weight 4) is used and rotameter shows the same reading, the flow rate (cc/sec) is

A. 26
B. 42
C. 269
D. 325

Question 389

A weir is used to measure the large water discharge rate from a river or from an open channel. A weir is not of __________ shape.

A. Circular
B. Rectangular
C. Triangular
D. Trapezoidal

Question 390

A stream tube is that, which has __________ cross-section entirely bounded by stream lines.

A. A circular
B. Any convenient
C. A small
D. A large

Question 391

When the pipe Reynold's number is 6000, the flow is generally

A. Viscous
B. Laminar
C. Turbulent
D. Transition

Question 392

Which of the following is a dimensionless parameter?

A. Angular velocity
B. Specific weight
C. Kinematic viscosity
D. None of these

Question 393

For very low pressure and high discharge rate, the compressor used is a/an __________ compressor.

A. Axial
B. Reciprocating
C. Rotary
D. None of these

Question 394

Capacity of a hydraulic accumulator is defined in terms of maximum

A. Amount of energy stored
B. Flow rate through accumulator
C. Rate of falling of ram
D. Volume available in the cylinder

Question 395

Which is not a variable head meter?

A. Venturimeter
B. Pitot tube
C. Rotameter
D. None of these

Question 396

One poise (unit of absolute/dynamic viscosity) is equivalent to one

A. Gm/cm². sec
B. Gm/cm. sec
C. Cm²/sec
D. M²/sec

Question 397

Poise is converted into stoke by

A. Multiplying with density (gm/c.c)
B. Dividing by density (gm/c.c)
C. Multiplying with specific gravity
D. Dividing by specific gravity

Question 398

Fluidised beds are formed, when the

A. Fluid friction is zero
B. Gravity force is less than the fluid friction
C. Pressure forces equal gravity forces
D. Sum of the fluid friction and pressure forces is equal and opposite to gravity forces

Question 399

Isotropic turbulence occurs

A. Where there is no velocity gradient
B. At higher temperatures
C. Only in Newtonion fluids
D. None of these

Question 400

The momentum correction factor for the velocity distribution of laminar flow is

A. 1.3
B. 1.66
C. 2.5
D. None of these

Question 401

The losses in open channel flow generally vary as the

A. Inverse of the roughness
B. First power of the roughness
C. Square of the velocity
D. Inverse square of hydraulic radius

Question 402

What is the unit of kinematic viscosity in SI unit?

A. m²/sec
B. N/m² . sec
C. Kg . sec/m
D. None of these

Question 403

If Blausius or Darcey friction factor is 'f₁' then the Fanning friction factor is equal to

A. f₁/4
B. 4F₂
C. 2f₁
D. f₁/2

Question 404

Nature of fluid flow during the opening of a valve in a pipeline is

A. Laminar
D. Uniform

Question 405

The equivalent diameter for pressure drop calculation for a fluid flowing through a rectangular cross-section channels having sides 'x' & 'y' is given by

A. 2xy/(x+y)
B. xy/(x+y)
C. (x+y)/2xy
D. (x+y)/xy

Question 406

Pick out the wrong statement about cavitation.

A. Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation
B. Cavitation may be caused due to boiling of liquid by decreasing the pressure resulting in formation & collapse of vapor cavities
C. Cavitation begins at higher static pressure and lower velocity in larger diameter pipelines resulting in audible noise
D. Large scale cavitation can not damage pipeline, restrict fluid flow and damage steam turbine blades

Question 407

__________ forces act on a particle moving through a stationary fluid.

A. Gravity
B. Drag
C. Buoyant
D. All of the above

Question 408

Stoke's law is valid, when NNRe,p is less than

A. 2
B. 100
C. 2100
D. 700

Question 409

Pick out the wrong statement.

A. The eddy viscosity is a function of the type of turbulence involved
B. The eddy viscosity is a fluid property
C. The viscosity of gas increases with increase in temperature
D. The viscosity of a liquid increases with decrease in temperature

Question 410

Correction for capillary effect in manometers (used for pressure measurement) need not be applied, if diameter of the manometer tube is __________ mm.

A. < 4
B. > 4
C. > 12.5
D. < 10

Question 411

__________ forces do not act in case of fluid flow.

A. Elastic
B. Tensile
C. Vibratory
D. Centrifugal

Question 412

Which of the following is not an advantage of fluidisation from transfer operation point of view?

A. Intimate contact of the fluid with all parts of the solid particles
B. Lower fluid pumping power requirement
C. Minimisation of temperature variation
D. Prevention of particle seggregation

Question 413

Dimension of absolute viscosity is

A. ML⁻¹T⁻¹
B. MLT⁻¹
C. ML⁻¹T
D. MLT

Question 414

One dimensional fluid flow implies the

A. Flow in straight lines only
B. Uniform flow
D. Flow in which transverse components are zero

Question 415

Equivalent length of a pipe fitting is

A. Dependent on Reynolds number
B. Independent of Reynolds number
C. Dependent on the length of the pipe
D. None of these

Question 416

Pick out the correct statement pertaining to venturimeter.

A. A venturimeter with a fixed pressure drop discharges more, when the flow is vertically downward, than when the flow is vertically upward
B. The co-efficient of contraction of a venturimeter is always unity
C. For a fixed pressure drop, the discharge of a gas through a venturimeter is greater, when compressibility is taken into account, than when it is neglected
D. None of these

Question 417

With increase in the ratio of orifice diameter to pipe diameter, the fraction of the orifice pressure differential that is permanently lost

A. Increases
B. Decreases
C. Remains unchanged
D. Increases exponentially

Question 418

Self-priming centrifugal pump can be used for

A. Booster service
B. Pumping liquid fertilisers (e.g. liquid NH₃)
C. Pumping industrial wastes
D. All of the above

Question 419

For laminar flow of Newtonion fluids through a circular pipe, for a given pressure drop and length & diameter of pipe, the velocity of fluid is proportional to(where, μ = fluid viscosity )

A. μ
B. 1/μ
C. √μ
D. 1/√μ

Question 420

Which of the following equations is valid for laminar flow of a fluid through packed bed?

A. Fanning equation
B. Kozney - Karman equation
C. Hagen - Poiseuille equation
D. Blake - Plummer equation

Question 421

Fanning friction factor for laminar flow of fluid in a circular pipe is

A. Not a function of the roughness of pipe wall
B. Inversely proportional to Reynolds number
C. Both A and B
D. Neither A nor B

Question 422

The distribution of shear stress in a stream of fluid in a circular tube is

A. Linear with radius for turbulent flow only
B. Linear with radius for laminar flow only
C. Linear with radius for both laminar & turbulent flow
D. Parabolic with radius for both laminar & turbulent flow

Question 423

Purpose of hydraulic accumulator is to

A. Ensure intermittant supply of hydraulic pressure
B. Increase the pressure and store/ accumulate it
C. Accumulate pressure to increase force
D. Generate high pressure to operate hydraulic machines like cranes, lifts, presses etc

Question 424

Which of the following properties of a fluid is responsible for offering resistance to shear?

A. Surface tension
B. Viscosity
C. Specific gravity
D. All of the above

Question 425

Which of the following is a Newtonian fluid?

A. Rubber latex
B. Sewage sludge
C. Quicksand
D. Non-colloidal solution

Question 426

An ideal plastic substance indicates no deformation, when stressed upto yield stress, but behaves like a Newtonion fluid beyond yield stress. Which of the following is an ideal plastic?

A. Sewage sludge
B. Rubber latex
C. Blood
D. Sugar solution

Question 427

Centrifugal pumps as compared to reciprocating pumps

A. Run at a lower speed for the same discharge
B. Do not need priming
C. Deliver fluid with pulsating/fluctuating discharge
D. Can be run with discharge line valve closed for a short interval

Question 428

In which of the following body shapes, the pressure drag is large compared to the friction drag?

A. Stream line body
B. Two dimensional body
C. Bluff body
D. None of these

Question 429

Which of the following denotes the effect of compressibility in fluid flow?

A. Weber number
B. Mach number
C. Euler number
D. Reynolds number

Question 430

In the low Reynolds number region, the drag force on a sphere is proportional to

A. V
B. V2
C. V4
D. V0.5

Question 431

Pick out the wrong statement:

A. The vacuum pressure is always the negative gauge pressure
B. The pressure of the liquid measured by a piezometer tube is the gauge pressure
C. Manometric liquid should have high surface tension
D. The point at which the resultant pressure on an immersed surface acts, is known as the centre of gravity

Question 432

The ratio of average fluid velocity to the maximum velocity in case of laminar flow of a Newtonion fluid in a circular pipe is

A. 0.5
B. 1
C. 2
D. 0.66

Question 433

Power required for mixing Newtonion fluids is a function of the

A. Speed of impeller, diameter of impeller & viscosity
B. Density & viscosity of fluid only
C. Density of fluid, viscosity of fluid & impeller dia only
D. None of these

Question 434

For pumping slurry, one can use a __________ pump.

A. Reciprocating
B. Diaphargm
C. Centrifugal
D. Pneumatic

Question 435

One dimensional flow implies

A. Flow in a straight line
D. A flow which does not account for changes in transverse direction

Question 436

One horsepower is equal to

A. 550 lbf.ft/second
B. 550 kgf.m/second
C. Both A and B
D. 550 lbf.ft./hr

Question 437

A mono pump is a __________ pump.

A. Centrifugal
B. Piston
C. Positive acting rotary
D. A group of vacuum

Question 438

For one dimensional flow of an incompressible fluid in unsteady state in x-direction, the continuity equation is given by

A. ∂u/∂x = 0
B. ∂(ρu)/∂x = 0
C. ∂u/∂x = - ∂ρ/∂t
D. ∂ρ/∂t = 0

Question 439

Velocity head on sudden enlargement in a horizontal pipe is converted into __________ head.

A. Elevation
B. Pressure
C. Both A and B
D. Neither A nor B

Question 440

Diaphragm valves are used for handling __________ fluids.

A. Corrosive
B. Viscous
C. Non-Newtonion
D. Solid suspended

Question 441

Pick out the wrong statement:

A. Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer
B. Blowers develop a maximum pressure of 2 atmospheres
C. Friction losses in pipe fittings are generally expressed in terms of velocity heads
D. Fanning friction factor in case of turbulent flow of liquids in pipe depends upon relative roughness & Reynolds number

Question 442

The velocity for subsonic flow in a pipeline

A. Increases in the downstream direction
B. Is constant
C. Decreases in the downstream direction
D. Is independent of the area of flow

Question 443

What is the value of co-efficient of discharge for square edged circular orifice (for β = 0.3 to 0.5)?

A. 0.61 - 0.63
B. 0.5 - 0.75
C. 0.75 - 0.90
D. 0.35 - 0.55

Question 444

The pump used for irrigation purposes is generally designed for

A. Large capacity & high head
B. Large capacity & low head
C. Small capacity & high head
D. Small capacity & low head

Question 445

Out of the following flow measuring devices, which one incurs the maximum installation cost as well as pressure loss?

A. Flow nozzle
B. Venturimeter
C. Rotameter
D. Orificemeter

Question 446

Open channel liquid flow is most conveniently measured by a

A. Hot wire anemometer
B. Notch
C. Rotameter
D. Segmental orifice

Question 447

Flow rate of high velocity flue gas discharged through a stack to the atmosphere can be most conveniently measured by a

A. Pitot tube
B. Manometer
C. Rotameter
D. None of these

Question 448

For liquid flow through a packed bed, the superficial velocity as compared to average velocity through the channel in the bed is

A. More
B. Less
C. Equal
D. Independent of porosity

Question 449

Bernoulli's equation describes the

A. Mechanical energy balance in potential flow
B. Kinetic energy balance in laminar flow
C. Mechanical energy balance in turbulent flow
D. Mechanical energy balance in boundary layer

Question 450

Air vessel provided in a reciprocating pump

A. Smoothens the flow by avoiding pulsations
B. Increases the volumetric efficiency of the pump
C. Saves the pump from the danger of cavitation
D. None of these

Question 451

With diminishing cross-sectional area in case of subsonic flow in a converging nozzle, the

A. Velocity increases
B. Pressure decreases
C. Both A and B
D. Neither A nor B

Question 452

The velocity distribution in direction normal to the direction of flow in plane Poiseuille flow is

A. Hyperbolic
B. Parabolic
C. Linear
D. None of these

Question 453

In which of the following cases, it is possible for flow to occur from low pressure to high pressure?

A. Flow of liquid upward in a vertical pipe
B. Flow through a converging section
C. Flow of air downward in a pipe
D. Impossible in a constant cross-section conduit

Question 454

For laminar flow of Newtonion fluid in a circular pipe, the velocity distribution is a function of the distance 'd' measured from the centre line of the pipe, and it follows a __________ relationship.

A. Logarithmic
B. Parabolic
C. Hyperbolic
D. Linear

Question 455

For turbulent flow in smooth circular pipe, the velocity distribution is a function of the distance 'd' measured from the wall of the pipe and the friction velocity 'v', and it follows a __________ relationship.

A. Logarithmic
B. Linear
C. Hyperbolic
D. Parabolic

Question 456

The head developed by a centrifugal pump is largely determined by the

A. Power of the pump
B. Nature of the liquid being pumped
C. Angle of the vanes and the speed of the tip of the impeller
D. Vapour pressure of the liquid

Question 457

Cavitation occurs in a centrifugal pump when the suction pressure is

A. Less than the vapour pressure of the liquid at that temperature
B. Greater than the vapour pressure of the liquid at that temperature
C. Equal to the vapour pressure
D. Equal to the developed head

Question 458

Draining of shallow pits or sump is done by a sump pump, which is a __________ pump.

A. Single stage vertical
B. Centrifugal
C. Plunger
D. Diffuser

Question 459

Specific speed for a centrifugal pump is

A. N√Q/H3/4
B. N√Q/H2/3
C. N√Q/H1/4
D. N√Q/H

Question 460

Venturimeters, orificemeters and nozzles are used to measure the fluid discharge from a pipeline. The average fluid velocity in a pipeline can be measured by a/an

A. Weir
B. Hot wire anemometer
C. Cup and vane aneometer
D. None of these

Question 461

Which of the following is an undesirable property of a manometric liquid?

A. Non-sticky & non-corrosive nature
B. High vapour pressure
C. Low viscosity & surface tension
D. Low co-efficient of thermal expansion

Question 462

Pick out the wrong statement.

A. Momentum transfer in laminar flow results from veclocity gradient
B. A fluid in equilibrium is not free from shear stress
C. The viscosity of a non-Newtonion fluid is a function of temperature only
D. Both B and C

Question 463

Which of the following is used for pumping crude oil from oil well?

A. Single stage centrifugal pump
B. Gear pump
C. Screw pump
D. Duplex/triplex reciprocating pump

Question 464

When the head pumped against is less than the head of the fluid used for pumping, the usual device is a/an

A. Ejector
B. Blower
C. Injector
D. Airlift

Question 465

The kinetic energy correction factor for velocity distribution of laminar flow is

A. 0.5
B. 1.66
C. 1
D. 2

Question 466

The Navier-Stokes equation deals with the law of conservation of

A. Mass
B. Energy
C. Both A and B
D. Momentum

Question 467

Critical velocity in a pipe flow

A. Increases as fluid viscosity increases
B. Increases as pipe diameter increases
C. Independent of fluid density
D. None of these

Question 468

The simple pitot tube does not measure the

A. Static pressure
B. Dynamic pressure
C. Velocity at the stagnation point
D. All of the above

Question 469

Pick out the wrong statement.

A. A fluid mass is free from shearing forces, when it is made to rotate with a uniform velocity
B. Newton's law of viscosity is not applicable to the turbulent flow of fluid with linear velocity distribution
C. Laminar flow of viscous liquids is involved in the lubrication of various types of bearings
D. Rise of water in capillary tubes reduces with the increasing diameter of capillary tubes

Question 470

The head loss in turbulent flow in pipe is proportional to(where, V = velocity of fluid through the pipe)

A. V²
B. 1/V²
C. 1/V
D. V

Question 471

For pipe flows, head is proportional to __________ at constant capacity(where, D = pipe diameter).

A. 1/D
B. 1/D²
C. 1/D⁵
D. D²

Question 472

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpmHead = 8 metresFlow = 1000 litres/minutes.If its speed is halved, the new discharge will be __________ litres/minute.

A. 500
B. 200
C. 1000
D. 750

Question 473

Pick out the correct statement.

A. Fanning friction factor is inversely proportional to Reynolds number always
B. The property of a randomly packed bed (with raschig rings) is given by the ratio of the total volume to the volume of voids in the bed
C. Mach number in an incompressible fluid is always unity
D. Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow

Question 474

Potential flow is characterised by the

A. Irrotational and frictionless flow
B. Irrotational and frictional flow
C. One in which dissipation of mechanical energy into heat occurs
D. Formation of eddies within the stream

Question 475

Multistage centrifugal pumps are generally used for

B. Low head but high discharge
C. Highly viscous liquid
D. Slurries of high solid concentration

Question 476

Remote control valve is a __________ valve.

A. Gate
B. Butterfly
C. Needle
D. Globe

Question 477

A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump

B. Capacity is reduced
C. Requires more power
D. All of the above

Question 478

In fluid flow, the boundary layer separation can not occur

A. In case of boundaries experiencing form drag
B. At points of abrupt changes in the flow directions
C. In laminar flow
D. None of these

Question 479

At what value of crank angle (roughly), no flow of water from or into the air vessel takes place in case of a double acting reciprocating pump?

A. 40° and 140°
B. 45° and 60°
C. 90° and 80°
D. 20° and 120°

Question 480

Select the correct practical example of steady non-uniform flow.

A. Motion of water around a ship in a lake
B. Motion of river around bridge piers
C. Steadily decreasing flow through a reducing section
D. Steadily increasing flow through a pipe

Question 481

In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the __________ efficiency.

A. Manometric
B. Mechanical
C. Volumetric
D. Overall

Question 482

__________ isused for measuring the static pressure exerted on the wall by a fluid flowing parallel to the wall in a pipeline.

A. Venturimeter
B. Pressure gauge
C. Pitot tube
D. Orificemeter

Question 483

Choose the correct set of dimensions of viscosity that are equivalent (where, F, M, L, T are dimensions for force, mass, length and time respectively).

A. FL⁻²T, ML⁻¹T⁻¹
B. FLT, ML⁻¹T⁻¹
C. ML⁻¹T⁻³, F⁻¹L²T
D. F-1L²T⁻¹, MLT⁻³

Question 484

Small pressure differences in liquids is measured using a/an

A. U-tube manometer
B. Inclined tube manometer
C. Pitot tube
D. None of these

Question 485

Bernoulli's equation accounts for the

A. Various momentums
B. Various masses
C. Different forms of mechanical energy
D. None of these

Question 486

For steady ideal fluid flow, the Bernoulli's equation states that the

A. Velocity is constant along a stream line
B. Energy is constant throughout the fluid
C. Energy is constant along a stream line, but may vary across stream lines
D. None of these

Question 487

Which of the following is not dimension-less?

A. Froude number
B. Kinematic viscosity
C. Pressure co-efficient
D. None of these

Question 488

Turbulent flow generally occurs for cases involving

A. Highly viscous fluid
B. Very narrow passages
C. Very slow motion
D. None of these

Question 489

Where does the maximum stress occur in case of laminar flow of incompressible fluid in a closed conduit of diameter 'd'?

A. At the centre
B. At d/4 from the wall
C. At the wall
D. At d/8 from the wall

Question 490

The ratio of maximum to average velocity in case of streamline flow between parallel plates is

A. 1
B. 1.5
C. 2
D. 2.5

Question 491

Pick out the wrong statement.

A. The shear stress at the pipe (dia = D, length = L) wall in case of laminar flow of Newtonion fluids is #####
B. In the equation, the value of
C. Shear stress for Newtonion fluid is proportional to the rate of shear in the direction perpendicular to motion
D. With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids

Question 492

The pressure head of a flow meter remains constant for

A. Venturimeter
B. Orificemeter
C. Rotameter
D. Pitot tube

Question 493

For the laminar flow of a fluid in a circular pipe of radius R, the Hagen-Poisseule equation predicts the volumetric flow rate to be proportional to

A. R
B. R2
C. R4
D. R0.5

Question 494

When a fluid flows over a solid surface, the

A. Velocity is uniform at any cross-section
B. Velocity gradient is zero at the solid surface
C. Resistance between the surface & the fluid is lesser as compared to that between the fluid layers themselves
D. Velocity is not zero at the solid surface

Question 495

Which of the following can be used for the direct measurement of volumetric flow rate of slurry?

A. Venturimeter
B. Orificemeter
C. Rotameter
D. Pitot tube

Question 496

In case of a pipe of constant cross-sectional area, the maximum fluid velocity obtainable is

A. The velocity of sound
B. Dependent on its cross-sectional area
C. Dependent on fluid viscosity
D. Dependent on fluid density

Question 497

Minimum porosity for fluidisation is

A. That corresponding to static bed
B. That corresponding to completely fluidised bed
C. The porosity of the bed when true fluidisation begins
D. Less than that of the' static bed

Question 498

For turbulent flow of newtonion fluid in a circular cross-section pipe, the ratio of maximum to average fluid velocity is

A. 0.5
B. 1
C. 0.66
D. < 0.5

Question 499

Efficiency of power transmission (η) through a circular pipe is given by (ht - hf)/ht, which has a maximum value of __________ percent.

A. 33:3
B. 50
C. 66.6
D. 88.8

Question 500

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpmHead = 8 metresFlow = 1000 litres/minutes.If its speed is halved, the power consumed now will be __________ hp.

A. 0.5
B. 2
C. 4
D. 1

Question 501

Pick out the wrong statement pertaining to fluid flow.

A. The ratio of average velocity to the maximum velocity for turbulent flow of Newtonion fluid in circular pipes is 0.5
B. The Newtonion fluid velocity in a circular pipe flow is maximum at the centre of the pipe
C. Navier-Stokes equation is applicable to the analysis of viscous flows
D. Hagen-Poiseuille equation is applicable to the laminar flow of Newtonion fluids

Question 502

The discharge co-efficient for an orificemeter does not depend upon the

A. Pipe length
B. Ratio of pipe diameter to orifice diameter
C. Type of orifice & the Reynolds number
D. Pipe diameter

Question 503

Location of vena-contracta in an orificemeter does not depend upon the

A. Type of orifice
B. Density, viscosity & compressibility of the fluid
C. Ratio of pipe diameter to orifice diameter
D. Pipe roughness

Question 504

Mercury is an ideal barometric fluid mainly due to its

A. High density
B. Low compressibility
C. Low capillary action
D. Very low vapor pressure

Question 505

The velocity profile for a Bingham plastic fluid flowing (under laminar conditions) in a pipe is

A. Parabolic
B. Flat
C. Flat near the wall and parabolic in the middle
D. Parabolic near the wall and flat in the middle

Question 506

A streamline is a line in flow field,

A. That is traced by all the fluid particles passing through a given point
B. Along which a fluid particle travels
C. Such that at every point on it, the velocity is tangential to it
D. None of these

Question 507

Hot wire anemometer is used to measure the

A. Velocity of liquids
B. Temperature of liquids
C. Velocity of gases
D. Pressure of liquids

Question 508

A pipe is defined as 'hydraulically smooth', if the friction factor

A. Is not a function of Reynolds number
B. For a given Reynolds number remains constant even on further smoothening of the pipe
C. Is zero irrespective of the Reynolds number
D. None of these

Question 509

Higher specific speed (200-500) of a centrifugal pump indicates that the pump is of __________ flow type.

A. Axial
C. Mixed
D. None of these

Question 510

In a/an __________ , the flow rate of fluids is obtained by measuring the difference between the impact and the static pressure.

A. Rotameter
B. Pitot tube
C. Venturimeter
D. Flow nozzle

Question 511

In a stabilised soap bubble, pressure inside it compared to external pressure is

A. More
B. Less
C. Same
D. Unpredictable

Question 512

The pump impeller and the turbine runner in a hydraulic torque converter

A. Have the same diameter
B. Have different diameters
C. Are directly coupled
D. None of these

Question 513

Rubber latex is an example of __________ fluid.

A. Dilatent
B. Newtonion
C. Pseudoplastic
D. Bingham plastic

Question 514

Paper pulp is an example of __________ fluid.

A. Dilatant
B. Bingham plastic
C. Newtonion
D. Pseudoplastic

Question 515

Forces acting on a particle settling in fluid are __________ forces.

A. Gravitational & buoyant
B. Centrifugal & drag
C. Gravitational or centrifugal buoyant drag
D. External, drag & viscous

Question 516

Pick out the wrong statement.

A. In a static mass of liquid, the pressure at a point is the same for all liquids
B. Pressure decreases exponentially with elevation in an isothermal atmosphere
C. Atmospheric pressure = absolute pressure-gage pressure
D. As per Pascal's law, the pressure at a point in a static or uniformly moving fluid is equal in all directions

Question 517

Existence of boundary layer in fluid flow is because of the

A. Surface tension
B. Fluid density
C. Fluid viscosity
D. Gravity forces

Question 518

Acceleration head in a reciprocating pump

A. Increases the work done during delivery stroke
B. Decreases the work done during suction stroke
C. Does not change the work requirement of the pump
D. Increases the work done during suction stroke

Question 519

The continuity equation in ideal fluid flow states that

A. Net rate of inflow into any small volume must be zero
B. Energy is not constant along a streamline
C. Energy is constant along a streamline
D. There exists a velocity potential

Question 520

Baffles in mixing tanks are provided to

A. Reduce swirling and vortex formation
B. Increase the structural strength of the tank
C. Aid in rotational flow
D. None of these

Question 521

Dean number is concerned with the

A. Fluid-particle interaction
B. Fluid flow through helical pipes
C. Power consumption in agitated vessels
D. Psychrometry

Question 522

Which of the following assumptions enables the Euler's equation of motion to be integrated?

A. The fluid is incompressible
B. The fluid is non-viscous
C. The continuity equation is satisfied
D. The flow is rotational and incompressible

Question 523

Flow measurement in an open channel is done by a/an

A. Venturimeter
B. Orificemeter
C. Weir
D. Rotameter

Question 524

Theoretical head developed by a centrifugal pump does not depend upon the __________ the impeller.

B. Speed of
C. Fluid velocity leaving
D. None of these

Question 525

In case of a centrifugal pump, the theoretical head developed is dependent on the __________ the impeller.

A. Speed of
B. Diameter of
C. Fluid velocity leaving
D. All of the above

Question 526

N. second/m² is

A. The S.I. unit of dynamic viscosity
B. The S.I. unit of kinematic viscosity
C. Equivalent to one poise
D. Equivalent to one stoke

Question 527

Discharge in laminar flow through a pipe varies

A. As the square of the radius
B. Inversely as the pressure drop
C. Inversely as the viscosity
D. As the square of the diameter

Question 528

In the complete turbulence zone (in rough pipes), the

A. Rough and smooth pipes have the same friction factor
B. Laminar film covers the roughness projections
C. Friction factor depends upon NRe only
D. Friction factor is independent of the relative roughness

Question 529

What is the speed of sound (m/sec) in ordinary water?

A. 1500
B. 330
C. 1000
D. 3000

Question 530

The effect of solid boundary on the fluid flow is confined to the boundary layer, except for fluids

A. Having high viscosities
B. Moving at low velocities
C. Both A and B
D. Neither A nor B

Question 531

In an incompressible flow of fluid, the fluid

A. Temperature remains constant
B. Compressibility is greater than zero
C. Density does not change with pressure & temperature
D. Is frictionless

Question 532

The dimension of kinematic viscosity is

A. ML⁻²T⁻¹
B. L²T⁻¹
C. ML⁻²T⁻²
D. None of these

Question 533

Dimension of kinematic viscosity is

A. MLT⁻¹
B. L² . T⁻¹
C. L²T
D. L² . T⁻²

Question 534

The drag co-efficient for a bacterium moving in water at 1 mm/s, will be of the following order of magnitude (assume size of the bacterium to be 1 micron and kinematic viscosity of water to be 10⁻⁶m²/s).

A. 24000
B. 24
C. 0.24
D. 0.44

Question 535

The ratio of hydrodynamic boundary layer to thermal boundary layer thickness in case of liquid metals is

A. < 1
B. 1
C. > 1
D. 2

Question 536

The hydraulic radius for flow in a rectangular duct of cross-sectional dimension H, W is

A. √(HW/π)
B. HW/2(H + W)²
C. HW/4(H + W)²
D. 2HW/(H + W)²

Question 537

For water, when the pressure increases, the viscosity

A. Also increases
B. Decreases
C. Remains constant
D. First decreases, and then increases

Question 538

Boundary layer thickness in laminar flow over a flat plate increases as(where, d = distance from the leading edge.)

A. √d
B. d1/3
C. d2
D. d2/3

Question 539

Boundary layer thickness in turbulent flow over a flat plate increases as(where, d = distance from the leading edge.)

A. √d
B. d2/3
C. d4/5
D. d1/3

Question 540

A. Conditions change steadily with time
B. Conditions are the same at the adjacent points at any instant
C. Conditions do not change with time at any point
D. Rate of the velocity change is constant

Question 541

The Stoke's stream function applies to the

A. Irrotational flow only
B. Ideal/non-viscous fluids only
C. Cases of axial symmetry
D. None of these

Question 542

In case of turbulent flow of a Newtonion fluid in a straight pipe, the maximum velocity is equal to (where, Vavg = average fluid velocity)

A. Vavg
B. 1.2 Vavg
C. 1.5 Vavg
D. 1.8 Vavg

Question 543

For Laminar flow through a packed bed, the pressure drop is proportional to (Vs is the superficial liquid velocity and Dp is the particle diameter)

A. Vs/Dp²
B. Vs²/Dp²
C. Vs²/Dp³
D. Vs/Dp³

Question 544

The equation given below is called the __________ . f-0.5 = 4.07 loge (NRe√f)-0.6

A. Colebrook formula
B. Von-Karman equation
C. Fanning equation
D. None of these

Question 545

The fluid velocity varies as the square root of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop fo __________ fluid.

A. Dilatant
B. Pseudoplastic
C. Bingham plastic
D. Newtonion

Question 546

Permanent loss in a venturimeter is about __________ percent of the pressure drop in theupstream cone.

A. 1
B. 10
C. 40
D. 70

Question 547

The pressure drop per unit length of pipe incurred by a fluid 'X' flowing through pipe is Δp. If another fluid 'Y' having both the specific gravity & density just double of that of fluid 'X', flows through the same pipe at the same flow rate/average velocity, then the pressure drop in this case will be

A. Δp
B. 2Δp
C. Δp²
D. Δp/2

Question 548

The simple pitot tube measures the __________ pressure.

A. Static
B. Dynamic
C. Total
D. None of these

Question 549

The peripherial velocity at inlet of a centrifugal pump having inlet diameter of 25 cms and rotating at 950 rpm is __________ m/sec.

A. 1.8
B. 12.4
C. 186.2
D. 736.4

Question 550

Which of the following is not a dimension-less parameter?

A. Euler number
B. Specific gravity
C. Fanning friction factor
D. None of these

Question 551

Which of the following is not a dimension-less parameter?

A. Pressure-co-efficient
B. Froude number
C. Kinematic viscosity
D. Weber number

Question 552

The continuity equation

A. Relates mass flow rate along a stream tube
B. Relates work and energy
C. Stipulates that Newton's second law of motion must be satisfied at every point in the fluid
D. None of these

Question 553

Bernoulli's equation is not applicable, when the flow is

A. Irrotational
B. Incompressible
C. Viscous
D. All of the above

Question 554

Permanent pressure loss in a well designed venturimeter is about __________ percent of the venturi differential.

A. 1
B. 10
C. 30
D. 50

Question 555

The velocity profile exhibited by laminar flow of Newtonion fluids is such that the velocity distribution w.r.t. radius of the circular pipe is a/an __________ with the apex at the centre line of the pipe.

A. Hyperbola
B. Parabola
C. Semi-circle
D. Semi-ellipse

Question 556

For laminar flow of a shear thinning liquid in a pipe, if the volumetric flow rate is doubled, the pressure gradient will increase by a factor of

A. 2
B. <2
C. >2
D. 1-2

Question 557

Specific speed of a centrifugal pump relates it with another pump having the

A. Dynamic similarity
B. Same efficiency
C. Same speed
D. Geometrical similarity

Question 558

High specific speed of a pump implies that, it is a/an __________ pump.

A. Centrifugal
B. Mixed flow
C. Axial flow
D. None of these

Question 559

Low specific speed of a pump implies that, it is a/an __________ pump.

A. Axial flow
B. Centrifugal
C. Mixed flow
D. None of these

Question 560

The temperature in isentropic flow

A. Does not depend on Mach number
B. Depends on Mach number only
C. Cannot drop and then increase again downstream
D. None of these

Question 561

Choose the set of pressure intensities that are equivalent.

A. 4.33 psi, 10 ft. of water, 8.83 inches of Hg
B. 4.33 psi, 10 ft. of water, 20.7 inches of Hg
C. 10 psi, 19.7 ft. of water, 23.3 inches of Hg
D. 10 psi, 19.7 ft. of water, 5.3 inches of Hg

Question 562

With increase in the ratio of orifice diameter to pipe diameter in case of an orificemeter, the overall pressure loss

A. Decreases
B. Increases
C. Remains constant
D. Increases linearly

Question 563

Laminar flow is characterised by the nonexistence of

A. Pressure fluctuation
B. Eddies
C. Deviating velocities
D. All of the above

Question 564

Terminal velocity is

A. A constant velocity with no acceleration
B. A fluctuating velocity
C. Attained after moving one-half of total distance
D. None of these

Question 565

A piezometer opening measures the __________ fluid pressure.

A. Static
B. Undisturbed
C. Total
D. Dynamic

Question 566

The centre of pressure is

A. Always below the centroid of the area
B. Always above the centroid of the area
C. A point on the line of action of the resultant force
D. At the centroid of the submerged area

Question 567

The continuity equation

A. Is independent of the compressibility of the fluid
B. Is dependent upon the viscosity of the fluid
C. Represents the conservation of mass
D. None of these

Question 568

The friction factor is

A. Always inversely proportional to the Reynolds number
B. Not dimensionless
C. Not dependent on the roughness of the pipe
D. None of these

Question 569

The lift of a ballon is

A. Increased, as it rises to a higher altitude
B. Due to the weight of the atmospheric air, that it displaces
C. Not dependent on the temperature of the atmosphere
D. None of these

Question 570

The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades.

A. Inlet tip of a blade curves in a direction opposite to that
B. Outlet tip of a blade curves in a direction opposite to that
C. Inlet tip of a blade is towards the direction
D. Outlet tip of a blade is towards the direction

Question 571

A centrifugal pump used to pump water is used to pump an oil with specific gravity of 0.8 at the same rate. The power consumption will now

A. Increase
B. Decrease
C. Remain same
D. Data insufficient to predict

Question 572

The Prandtl mixing length is

A. Zero at the pipe wall and is a universal constant
B. Independent of radial distance from the pipe axis
C. Independent of the shear stress
D. Useful for computing laminar flow problems

Question 573

Check valve provided in the discharge line of a centrifugal pump serves the purpose of controlling the

A. Back flow of fluid in the event of stoppage of pump
B. Discharge pressure
C. Flow of liquid during operation of the pump
D. All of the above

Question 574

The unit of velocity head is

A. ft-lb/sec
B. ft-lb/ft³
C. ft-lbf/lb
D. ft-lbf/sec

Question 575

Which of the following exemplifies a three dimensional fluid flow ?

A. Fluid flow at the inlet to a nozzle
B. Fluid flow between parallel plates
C. Viscous fluid flow between converging plates
D. None of these

Question 576

The ratio of actual discharge to theoretical discharge through an orifice is equal to

A. Cc . Cv
B. Cc . Cd
C. Cv . Cd
D. Cd/Cv

Question 577

A differential pressure cell is used for

A. Measuring small pressure difference in gases
B. Measuring small pressure difference in liquids
C. Remote recording of pressure difference
D. Measuring the difference of the impact & the static pressure

Question 578

In Newton's law range, the drag co-efficient for the motion of spherical particle in a stationary fluid is

A. 0.44
B. 0.044
C. 4.4
D. 44

Question 579

Volume of liquid displaced by a floating body is equivalent to its

A. Own weight
B. Submerged weight
C. Own volume
D. Submerged volume

Question 580

Euler's equation of motion is a statement expressing

A. Conservation of mass
B. Conservation of energy
C. Newton's first law of motion
D. Newton's second law of motion

Question 581

Steady fluid flow occurs, when the derivative of flow variables satisfy the following condition.

A. ∂/∂s = 0
B. ∂/∂t = 0
C. ∂/∂s = constant
D. ∂/∂t = constant

Question 582

Uniform fluid flow occurs, when the derivative of the flow variables satisfy the following condition.

A. ∂/∂t = 0
B. ∂/∂t = constant
C. ∂/∂s = 0
D. ∂/∂t = constant

Question 583

In frictional fluid flow, the quantity, P/ρ + V²/2gc + gz/gc, is

A. Constant along a streamline
B. Not constant along a streamline
C. Increased in the direction of flow
D. None of these

Question 584

Rotary vacuum pumps can reduce the absolute pressure to as low as __________ mm Hg.

A. 1
B. 0.1
C. 0.01
D. 0.001

Question 585

Water hammer is caused, when water flowing in a pipe is suddenly brought to rest by closing the valve. The extent of pressure thus produced due to water hammer depends on the

A. Pipe length
B. Fluid velocity in the pipe
C. Time taken to close the valve
D. All of the above

Question 586

As per Newton's law of viscosity, the shear stress for a given rate of angular deformation of fluid is proportional to(where, μ = fluid viscosity)

A. 1/μ
B. μ
C. μ²
D. 1/μ²

Question 587

Toothpaste is a

A. Bingham plastic
B. Pseudoplastic
C. Newtonion liquid
D. Dilatent

Question 588

Path followed by water jet issuing from the bottom of a water tank will be a

A. Parabola (vertex being at the opening)
B. Hyperbola
C. Horizontal straight line
D. Zig-zag path (which is geometrically undefined)

Question 589

Turbine impeller

B. Produces only tangential current
C. Is effective over wide range of viscosities
D. Does not produce tangential current

Question 590

Transition from laminar flow to turbulent flow is aided by the

A. Surface roughness and curvature (i.e.sharp corners)
B. Vibration
C. Pressure gradient and the compressibility of the flowing medium
D. All of the above

Question 591

Capillary tube method of viscosity measurement is based on the

A. Hagen-Poiseulle's equation
B. Stoke's law
C. Navier-stokes equation
D. None of these

Question 592

In deriving Bernoulli's equation, fluid is assumed to be

A. Incompressible, frictionless, steady, along a streamline
B. Uniform, steady, incompressible, along a streamline
C. Steady, density being pressure dependent, frictionless
D. None of these

Question 593

Cp/Cv is termed as

B. Mach number
C. Weber number
D. Prandtl number

Question 594

The equivalent diameter for flow through a rectangular duct of width B and height H is

A. HB/2(H + B)
B. HB/(H + B)
C. 2HB/(H + B)
D. 4HB/(H + B)

Question 595

As the velocity V and thus the Reynolds number of a flow past a sphere increases from very low value, the drag force for Re << 1

A. Increases linearly with V
B. Decreases linearly with V
C. Decreases as V²
D. None of these

Question 596

Delivery of insufficient quantity of liquid by a pump may be caused by

A. Air leak in the inlet
B. Low rpm
C. Too high a lift
D. All of the above

Question 597

Design of the casing of centrifugal pump should be such as to minimise the

A. Back flow through impeller
D. None of these

Question 598

A lubricant 100 times more viscous than water would have a viscosity (in Pa.s)

A. 0.01
B. 0.1
C. 1
D. 10

Question 599

Pressure gradient in the pipe flow is influenced by the

A. Diameter of pipe
B. Velocity of the fluid
C. Density & viscosity of the fluid
D. All of the above

Question 600

In case of supersonic flow of a fluid through pipeline, the 'Mach number' is

A. 0
B. 1
C. < 1
D. > 1

Question 601

Plunger pumps are used for

A. Higher pressure
B. Slurries
C. Viscous mass
D. None of these

Question 602

Bernoull's equation does not apply to the functioning of a/an

A. Venturimeter
B. Orificem
C. Pitot tube
D. None of these

Question 603

Potential flow is the flow of

A. Compressible fluids with shear
B. Compressible fluids with no shear
C. Incompressible fluids with shear
D. Incompressible fluids with no shear

Question 604

Power number is the ratio of

A. Drag stress to inertial stress
B. Inertial stress to drag stress
C. Inertial stress to gravitational stress
D. Gravitational stress to drag stress

Question 605

Prandtl mixing length is

A. Applicable to laminar flow problems
B. A universal constant
C. Zero at the pipe wall
D. None of these

Question 606

Unsteady uniform flow is represented by flow through a/an

A. Long pipe at constant rate
B. Long pipe at decreasing rate
C. Expanding tube at increasing rate
D. Expanding tube at constant rate

Question 607

Unsteady non-uniform flow is represented by flow through a/an

A. Long pipe at constant rate
B. Long pipe at decreasing rate
C. Expanding tube at increasing rate
D. Expanding tube at constant rate

Question 608

Steady uniform flow is represented by flow through a/an

A. Long pipe at constant rate
B. Long pipe at decreasing rate
C. Expanding tube at constant rate
D. None of these

Question 609

The co-efficient of drag and lift for an incompressible fluid depends on the

A. Reynolds number
B. Froude number
C. Mach number
D. All of the above

Question 610

__________ flow means the flow of incompressible fluid with no shear.

A. Potential
B. Streamline
C. Creep
D. Boundary layer

Question 611

For the same flow rate of a fluid, the pressure drop is the least for

A. Venturimeter
B. Orificemeter
C. Flow-nozzle
D. Δp is same for all

Question 612

Isothermal turbulent flow of a fluid results in decrease of its pressure, which depends on the

A. Wall roughness
B. Reynolds number
C. Both A and B
D. Neither A nor B

Question 613

Propellers are

A. Axial flow mixers
B. Low speed impeller
C. Used for mixingliquids of high viscosity

Question 614

Horsepower requirement for given pump capacity depends upon the

A. Specific gravity of the liquid
B. Suction lift
D. All of the above

Question 615

Working of a __________ pump characterises mixed flow.

A. Turbine
B. Piston
C. Diaphragm
D. None of these

Question 616

Which is the correct relationship for a centrifugal pump? (where, D = Impeller diameter, inches H = Head developed, ft of liquid pumped N = Speed of pump, rpm)

A. D = 1840 H0.5/N
B. D = 1840 N/H0.5
C. H = 1840 D0.5/N
D. D = 1840 H/N

Question 617

Purpose of air lift pump is to

A. Compress air
B. Lift compressed air
C. Lift water from a well by using compressed air
D. Lift air under negative pressure

Question 618

A pump operating under specific conditions delivers insufficient quantity of liquid. This may be set right by

A. Decreasing the size of the inlet pipe
B. Increasing the size of the inlet pipe
C. Lowering the pump position
D. Both B and C

Question 619

A pressure of 10 m head of water is equivalent to __________ kN/m².

A. 98
B. 147
C. 196
D. 49

Question 620

Viscosity of water at 40°C lies in the range of

A. 1 x 10⁻³ to 2 x 10⁻³ kg/m.s
B. 0.5 x 10⁻³ to 1 x 10⁻³ kg/m.s
C. 1 to 2 kg/m.s
D. 0.5 to 1 kg/m.s

Question 621

Which of the following conditions must be satisfied for lift force to be developed?

A. The body should be bluff body
B. The body should be stream lined
C. Circulation around the body is essentially required
D. The main stream velocity must approach the velocity of sound in that fluid medium

Question 622

Pipes having diameter 14 inches or more are designated by their

A. Outside diameter
B. Inside diameter
C. Schedule number
D. None of these

Question 623

For flow past a flat plate, if x is the distance along the plate in the direction of flow, the boundary layer thickness is proportional to

A. √x
B. 1/√x
C. X
D. 1/x

Question 624

Power requirement of fans having constant wheel diameter varies __________ fan speed.

A. As square of
B. Directly as
C. As cube of
D. None of these

Question 625

Which of the following equations applies to the fluid flow through a packed bed for very large Reynolds number?

A. Fanning equation
B. Blake-Pllummer equation
C. Hagen-Poiseulle equation
D. Kozney-Karman equation

Question 626

Major loss in sudden contraction in pipe flow is due to

A. Boundary friction
B. Flow contraction
C. Expansion of flow after sudden contraction
D. None of these

Question 627

The Prandtl pitot tube measures the

A. Velocity at a point in the flow
B. Pressure at a point
C. Average flow velocity
D. Pressure difference in pipe flow

Question 628

Pick out the correct statement.

A. Human blood is a Newtonion fluid
B. A Newtonion fluid obeys Newton's law of cooling
C. For a non-Newtonion fluid, a straight line passes through the origin in a plot between shear stress and shear gradient
D. Thin lubricating oil is an example of a non-Newtonion fluid

Question 629

With decrease in particle size to be fluidised by a particular fluid, the operating range of fluidisation velocity

A. Widens
B. Squeezes
C. Does not change
D. Unpredictable from the data

Question 630

Hydraulic __________ works on the principle of Pascal's law of transmission of fluid pressure.

A. Press
B. Turbine
C. Pump
D. Coupling

Question 631

Mach number is defined as the ratio of the local flow velocity to the sonic velocity in the fluid. For what value of Mach number, the gases are considered incompressible?

A. < 0.3
B. > 3
C. 50
D. 1

Question 632

The fluid velocity varies as the square of the cylindrical pipe diameter, in case of steady state laminar flow at constant pressure drop, for __________ fluid.

A. Newtonion
B. Dilatant
C. Pseudoplastic
D. Non-Newtonion

Question 633

Enamels and paints are generally __________ fluid.

A. Reheopectic
B. Pseudo-plastic
C. Thixotropic
D. Dilatant

Question 634

In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where, T = absolute temperature )

A. 1/√T
B. 1/T
C. √T
D. T

Question 635

The pressure intensity is the same in all directions at a point in a fluid

A. Only when the fluid is frictionless
B. Only when the fluid is at rest having zero velocity
C. When there is no motion of one fluid layer relative to an adjacent layer
D. Regardless of the motion of one fluid layer relative to an adjacent layer

Question 636

Working principle of manometer comprises of balancing a coloumn of liquid against the pressure to be measured. Inclined tube manometer is especially used for the measurement of __________ pressure.

A. Small differential
B. Atmospheric
C. Absolute
D. Gage

Question 637

Differential manometer measures the

A. Atmospheric pressure
B. Sub-atmospheric pressure
C. Pressure difference between two points
D. None of these

Question 638

Pitot tube measures the __________ of a fluid.

A. Pressure
B. Average velocity
C. Average flow rate
D. Point velocity

Question 639

What is the maximum theoretical suction lift (metres) of a reciprocating pump?

A. 5
B. 10
C. 50
D. 100

Question 640

In an incompressible fluid, the density is

A. Greatly affected by moderate changes in pressure
B. Greatly affected only by moderate changes in temperature
C. Not affected with moderate change in temperature & pressure
D. Sensible to changes in both temperature & pressure

Question 641

The flow of gas along a pipe in the direction of decreasing pressure causes decrease in its

A. Viscosity
B. Specific volume
C. Velocity
D. None of these

Question 642

A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m³ ) is to be fluidised by water (density 1000 kg/m³ ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is

A. 4.4 KPa
B. 2.94 KPa
C. 3.7 KPa
D. None of these

Question 643

The maximum depth from which a centrifugal pump can draw water is

A. Dependent on the speed of the pump
B. Dependent on the power of the pump
C. 34 feet
D. 150 feet

Question 644

A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below :Δ P/L = 375 x 10³ VOM + 10.94 x 10⁶ V²OM (SI units) If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed ?

A. 0.2
B. 0.5
C. 0.7
D. 0.8

Question 645

The discharge through a V-notch weir varies as

A. H3/2
B. H1/2
C. H5/2
D. H2/3

Question 646

The pressure head on sudden contraction in a horizontal pipe is converted into the __________ head.

A. Elevation
B. Velocity
C. Both A and B
D. Neither A nor B

Question 647

The discharge through a semi-circular weir varies as (where, H = Head of liquid.)

A. H
B. H2
C. H3/2
D. H1/2

Question 648

Fluid flow in a/an __________ is an example of pressure flow.

A. Partially filled pipeline
B. Pipe
C. Open channel
D. River

Question 649

In case of unsteady fluid flow, conditions & flow pattern change with the passage of time at a position in a flow situation. Which of the following is an example of unsteady flow?

A. Discharge of water by a centrifugal pump being run at a constant rpm
B. Water flow in the suction and discharge pipe of a reciprocating pump
C. Water discharge from a vertical vessel in which constant level is maintained
D. Low velocity flow of a highly viscous liquid through a hydraulically smooth pipe

Question 650

__________ pumps are a group of vacuum pumps.

A. Hyter
B. Sump
C. Mono
D. Submerged

Question 651

A spherical particle is falling slow in a viscous liquid such that Reynolds number is less than 1. Which statement is correct for this situation?

A. Inertial and drag forces are important
B. Drag, gravitational and buoyancy forces are impportant
C. Drag force and gravitational forces are important
D. None of the above

Question 652

The time taken for gravity flow of a fixed volume of liquid (as in Redwood viscometer) is directly proportional to its

A. Absolute viscosity
B. Ratio of absolute viscosity to density
C. Density
D. Reynolds number

Question 653

Bernoulli's equation is dependent on the

A. First law of thermodynamics
B. Third law of thermodynamics
C. Law of conservation of momentum
D. None of these

Question 654

The speed of a sound wave in a gas is analogous to the speed of

A. An elementary wave in an open channel
B. Flow in an open channel
C. A disturbance travelling upstream in moving fluid
D. None of these

Question 655

Newton's law of viscosity relates the

A. Shear stress and velocity
B. Velocity gradient and pressure intensity
C. Shear stress and rate of angular deformation in a fluid
D. Pressure gradient and rate of angular deformation

Question 656

Priming is needed in a __________ pump.

A. Reciprocating
B. Gear
C. Centrifugal
D. Diaphragm

Question 657

A hydraulic press has a ram of 10 cms in diameter and a plunger of 1 cm in diameter. The force required on the plunger to raise a weight of 10 tons on the ram is __________ kg.

A. 10
B. 100
C. 1000
D. 10000

Question 658

The rate of change of moment of momentum represents the __________ by the fluid.

A. Torque applied
B. Force exerted
C. Work done
D. Power developed

Question 659

Venturimeter and orificemeter measures the __________ of the fluid.

A. Pressure
B. Maximum velocity
C. Average velocity
D. Point velocity

Question 660

Each term in Bernaulli's equation represents the __________ of the fluid.

A. Energy per unit mass
B. Energy per unit weight
C. Force per unit mass
D. None of these

Question 661

Drag force on the float of a rotameter is(where Q = flow rate of the )

A. ∝Q
B. ∝√Q
C. ∝Q²
D. Constant

Question 662

Which of the following facilitates close control of flow of fluids?

A. Gate valve
B. Globe valve
C. Butterfly valve
D. Check valve

Question 663

In area meter (e.g., rotameter), with increase in the fluid flow rate, the

A. Pressure drop increases linearly
B. Pressure drop is almost constant
C. Area through which fluid flows does not vary
D. None of these

Question 664

Hydraulic radius of 6" x 12" cross-section, is __________ inches.

A. 2
B. 0.5
C. 1.5
D. None of these

Question 665

In case of a __________ the energy of flow is considerably decreased downstream of the machine.

A. Blower
B. Turbine
C. Centrifugal pump
D. Centrifugal fan

Question 666

Select the correct statement.

A. The discharge through a venturimeter depends upon ?p only and is independent of orientation of the meter
B. A venturimeter with a given gage difference discharges at a greater rate, when the flow is vertically downward through it, than when the flow is vertically upward
C. For a given pressure difference, the discharge of gas is greater through a venturimeter, when compressibility is taken into account, than when it is neglected
D. The overall pressure loss is the same in a given pipe line, whether a venturimeter or a nozzle with the same throat dia is used

Question 667

The bulk modulus of elasticity of a liquid

A. Is zero for incompressible liquid
B. Decreases with pressure
C. Is independent of temperature & pressure
D. Increases with pressure

Question 668

Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the __________ decreases.

A. NPSH required
B. BHP required by the pump
C. Head of the liquid pumped
D. All of the above

Question 669

In laminar flow through a round tube, the discharge varies

A. Linearly as the viscosity
B. Inversely as the pressure drop
C. Inversely as the viscosity
D. As the square of the radius

Question 670

What is the ratio of displacement thickness to nominal thickness for a linear distribution of velocity in the boundary layer on a flat plate?

A. 0.5
B. 1
C. 1.5
D. 2

Question 671

The hydrodynamic and thermal boundary layers will merge, when

A. Prandtl number is one
B. Schmidt number tends to infinity
C. Nusselt number tends to infinity
D. Archimedes number is greater than 10000

Question 672

Unit of mass velocity is

A. Kg/hr
B. Kg/m². hr
C. Kg/m²
D. Kg/m³. hr

Question 673

Scale up of agitator design requires

A. Geometrical similarity only
B. Dynamic similarity only
C. Both geometrical and dynamic similarity
D. All of the above

Question 674

A centrifugal pump is called a turbine pump, if it is having a

A. Turbine type impeller
B. Vaned diffusion casing
C. Rotating vaned volute
D. None of these

Question 675

The head loss in turbulent flow in a pipe varies

A. As velocity
B. As (velocity)²
C. Inversely as the square of diameter
D. Inversely as the velocity

Question 676

The head loss in turbulent flow in a pipe varies

A. Directly as the velocity
B. Inversely as the square of the velocity
C. Approximately as the square of the velocity
D. Inversely as the square of the diameter

Question 677

A 2" gate valve fitted in a pipe is replaced by a similar globe valve. Pressure drop in gate valve was Δp. For the same discharge, the pressure drop across globe valve is

A. Δp
B. < Δp
C. > Δp
D. Δp²

Question 678

The fluid velocity varies as the cube of the cylinderical pipe diameter in case of steady state laminar flow at constant pressure drop for __________ fluid.

A. Newtonion
B. Pseudoplastic
C. Dilatent
D. Bingham plastic

Question 679

The __________ is measured by a piezometric opening.

A. Dynamic pressure
B. Static pressure
C. Total pressure
D. Point velocity

Question 680

Multistage compressors are used in industry, because they

A. Reduce the cost of compressor
B. Reduce the size requirement
C. Resemble closely to isothermal compression
D. Are easy to control

Question 681

Vane anemometer

A. Is an area meter
B. Is a variable head meter
C. Rotates an element at a speed determined by the velocity of the fluid in which the meter is immersed
D. None of these

Question 682

If three pipes of different diameters, lengths & friction factors are connected in parallel, then (where, Q = flow rate, V= fluid velocity f = friction factor).

A. Q = Q₁ + Q₂ + Q₃
B. V₁ = V₂ = V₃
C. Q₁ = Q₂ = Q₃
D. F = f₁ + f₂ + f₃

Question 683

Reynolds number for flow of water at room temperature through 2 cm dia pipe at an average velocity of 5 cm/sec is around

A. 2000
B. 10
C. 100
D. 1000

Question 684

A double acting reciprocating pump compared to a single acting pump (of almost same size working under same pressure levels) would give almost double

B. Discharge
C. Efficiency
D. None of these

Question 685

Volute type of casing is provided in a centrifugal pump to

C. Reduce the discharge fluctuation
D. Increase the discharge

Question 686

Which law/principle of solid mechanics is similar/equivalent to Newton's law of viscosity in fluid mechanics?

A. Archimedes principle
B. Newton
C. Hooke
D. Newton

Question 687

What causes cavitation in centrifugal pump?

A. High suction pressure
B. Low barometric pressure
C. Low suction pressure
D. High suction velocity

Question 688

For a stable equilibrium of a submerged body (where, G and B are centres of gravity & buoyancy respectively).

A. G is above B
B. B is above G
C. B & G coincide
D. None of these

Question 689

The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost are P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet.

A. P, Q and R
B. P and R
C. R and S
D. P, Rand S

Question 690

Momentum transfer in laminar flow of fluids results due to the

A. Viscosity
B. Density
D. None of these

Question 691

The terminal velocity of a solid spherical particle falling through a stationary fluid mass in the Stoke's law range is proportional to the

A. Inverse of fluid viscosity
B. Square of particle size
C. Difference in the densities of the particle & fluid
D. All of the above

Question 692

Cd is always __________ Cc.

A. Greater than
B. Less than
C. Equal to
D. Either more or less than

Question 693

Velocity distribution for flow between two fixed parallel plates

A. Varies parabolically across the section
B. Is constant over the entire cross-section
C. Is zero at the plates and increases linearly to the midplane
D. None of these

Question 694

A fluid is pumped at the rate of 10 lb/sec to a height of 55 ft. The horse power required is __________ hp.

A. 1
B. 10/55
C. 5.5
D. 1/55

Question 695

In case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, whereas for a hydraulically rough pipe, the resistance to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equal values of

A. Relative roughness
B. Absolute roughness
C. Friction co-efficient for flows at equal Reynold number
D. All of the above

Question 696

The most economical flow control valve for use with large diameter pipes is a

A. Butterfly valve
B. Globe valve
C. Needle valve
D. None of these

Question 697

Two dimensional stream function

A. Relates velocity and pressure
B. Is constant along a stream line
C. Is constant along an equipotential surface
D. None of these

Question 698

Rubber latex is an example of a __________ .fluid.

A. Pseudoplastic
B. Bingham plastic
C. Dilatent
D. Newtonion

Question 699

__________ is an example of axial flow impeller.

B. Turbine
C. Propeller
D. All of the above

Question 700

Water is flowing at 1 m/sec through a pipe (of 10 cm I.D) with a right angle bend. The force in Newtons exerted on the bend by water is

A. 10√2π
B. 5π/2
C. 5√2π
D. 5π/√2

Question 701

The unit of bulk modulus of elasticity for a liquid in S.I. unit is

A. N
B. N/m
C. N/m²
D. N/m³

Question 702

The most suitable flow measuring device for the fluid flow measurement in a very large diameter pipeline is a

A. Weir
B. Pitot tube
C. Kennison nozzle
D. V-notch

Question 703

Slurries can be most conveniently pumped by a __________ pump.

A. Screw
B. Reciprocating
C. Gear
D. Centrifugal

Question 704

Medium viscosity lubricating oil can be most ideally pumped by a __________ pump.

A. Vane
B. Piston
C. Centrifugal
D. Plunger

Question 705

Reynolds number for water flow through a tube of I.D. 5 cm is 1500. If a liquid of 5 centipoise viscosity and 0.8 specific gravity flows in the same pipe at the same velocity, then the pressure drop will

A. Increase
B. Decrease
C. Remain same
D. Data insufficient to predict pressure drop

Question 706

If two capillary tubes of dia 0.5 mm and 1 mm are dipped in a pot containing mercury, then the rise of mercury is

A. Same in both the tubes
B. Greater in 1 mm dia tube
C. Greater in 0.5 mm dia tube
D. Zero in both the tubes

Question 707

Boundary layer separation occurs when the

A. Pressure reaches a minimum
B. Cross-section of the channel is reduced
C. Valve is closed in a pipeline
D. Velocity of sound is reached

Question 708

A stream line is

A. Fixed in space in steady flow
B. Always the path of particle
C. Drawn normal to the velocity vector at every point
D. A line connecting the mid points of flow cross-section

Question 709

The unit of dynamic viscosity in SI unit is

A. kg/m . sec
B. N/m²
C. m² /sec
D. m/N. sec

Question 710

The value of critical Reynolds number for pipe flow is

A. 1300
B. 10000
C. 100000
D. None of these

Question 711

Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation?

A. Decrease in effect
B. Increase in thrust
C. Develops noise
D. Develops high pressure

Question 712

An equipotential line is __________ to the velocity vector at every point.

A. Normal
B. Normal
C. Tangential
D. None of these

Question 713

Steady non-uniform flow is exemplified by flow through a/an

A. Long pipe at constant rate
B. Long pipe at decreasing rate
C. Expanding tube at increasing rate
D. Expanding tube at constant rate

Question 714

Pressure drop in packed bed for turbulent flow is given by the __________ equation.

A. Kozney-Karman
B. Blake-Plummer
C. Leva's
D. Hagen-Poiseulle's

Question 715

Pressure drop in a packed bed for laminar flow is given by the __________ equation.

A. Kozney-Karman
B. Blake-Plummer
C. Leva's
D. Fanning friction factor

Question 716

Creeping flow around a sphere is defined, when particle Reynolds number is

A. < 2100
B. < 0.1
C. > 2.5
D. < 500

Question 717

Specific speed of a centrifugal pump depends upon the __________ head.

A. Suction
B. Delivery
C. Manometric
D. None of these

Question 718

The energy equation, E + P/ρ + V²/2g +gZ (E = internal energy/mass), is applicable to

A. Perfect gases only
B. Isothermal flow of gases
D. All of the above

Question 719

The dimension of dynamic viscosity is

A. ML⁻¹T⁻¹
B. L²T⁻¹
C. LT⁻²
D. ML⁻¹T⁻²

Question 720

Pick out the correct statement pertaining to transition/ entrance length in fluid flow.

A. The length of entrance region of pipe, in which full development of fluid flow takes place such that velocity profile does not change downstream, is called the transition length
B. Transition length for laminar flow of Newtonion fluids in a pipe of diameter 'd' is equal to 0.05. D.NRe
C. Transition length for turbulent flow of Newtonion fluids in a smooth pipe of diameter 'd' is equal to 50 D
D. All of the above

Question 721

Head developed by a centrifugal pump depends on its

A. Speed
B. Impeller diameter
C. Both A and B
D. Neither A nor B

Question 722

Each term of the Bernoulli's equation written in the form, P/ρ + g/gc .Z + v²/2gc = constant , represents the total energy per unit

A. Mass
B. Volume
C. Specific weight
D. None of these

Question 723

The rate of shear versus the shear stress curves are time dependent for __________ fluid.

A. Thixotropic
B. Rheopectic
C. Both A and B
D. Neither A nor B

Question 724

Boundary layer separation is caused by the

A. Reduction of pressure to vapour pressure
B. Boundary layer thickness reducing to zero
D. Reduction of pressure gradient to zero

Question 725

Boundary layer separation is caused by the

A. Reduction of pressure below vapour pressure
B. Reduction of pressure gradient to zero
D. Reduction of boundary layer thickness to zero

Question 726

In case of centrifugal fan or blower, the gas capacity varies as

A. Speed
B. (speed)2
C. (speed)3
D. (speed)0.5

Question 727

A fluid whose apparent viscosity increases with shear rate is termed as the __________ fluid.

A. Newtonion
B. Viscous
C. Dilatant
D. Non-viscous

Question 728

Which is the most efficient and best for measuring very small flow rate of gases?

A. Venturimeter
B. Orifice meter
C. Rotameter
D. Flow nozzle

Question 729

The pressure and power requirement of a gas fan at constant speed & capacity varies __________ the gas density.

A. Directly as
B. Inversely as square root of
C. Inversely as
D. As square of

Question 730

For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the

A. Square of the radial distance
C. Inverse of the radial distance
D. Elevation along vertical direction

Question 731

To handle smaller quantity of fluid at higher discharge pressure, use a __________ pump.

A. Reciprocating
B. Centrifugal
C. Volute
D. Rotary vacuum

Question 732

What is the ratio of fluid carrying capacity of two pipes having diameters d₁ and d₂ respectively?

A. (d₁/d₂)0.8
B. (d₁/d₂)0.5
C. (d₁/d₂)
D. (d₁/d₂)2

Question 733

What is the pipe called which lifts water from a reservoir to a greater height than the initial level in the supply reservoir?

A. Penstock
B. Siphon
C. Tunnel
D. Pressure pipeline

Question 734

Quicksand is an example of a __________ fluid.

A. Bingham plastic
B. Dilatent
C. Newtonion
D. Pseudoplastic

Question 735

Drag is the force component exerted on an immersed object,

A. Passing the centroid of the body at 60°to the direction of motion
B. The component being parallel to theflow direction
C. The component being normal to the flow direction
D. None of these

Question 736

In case of a pipe exit fitted with a nozzle, the

C. Power transmitted through the nozzle is maximum, when the head lost due to friction in the pipe is equal to one third of the total supply head
D. Both B and C

Question 737

Reynolds number is the ratio of

A. Viscous forces to gravity forces
B. Inertial forces to viscous forces
C. Viscous forces to inertial forces
D. Inertial forces to gravity forces

Question 738

The valve used for very remote and accurate control of fluid is a __________ valve.

A. Needle
B. Globe
C. Gate
D. Butterfly

Question 739

The terminal velocity of a particle moving through a fluid varies as dpn. What is the value of n' for Newton's law regime?

A. 0.5
B. 1
C. 1.5
D. 3

Question 740

Absolute viscosity of a fluid is a function of the __________ of the fluid.

A. Motion
B. Pressure & temperature
C. Shearing stress
D. Both B & C

Question 741

A free jet of water of cross-sectional area 0.01m² and a velocity of 20 m/s strikes a plate and then flows in a plane parallel to the plate as shown in the figure below. The horizontal component of the force on the support is

A. 200 N
B. 400 N
C. 2000 N
D. 4000 N

Question 742

Which of the following relationship is valid for the equilibrium position of the float in a rotameter ?(where, Df= Drag force on the float Bf = Buoyant force on the float Wf = Weight of the float)

A. Df + Bf = Wf
B. Df = Bf + Wf
C. Df + Bf + Wf =0
D. None of these

Question 743

With increasing flow rate, the hydraulic efficiency of a centrifugal pump

A. Monotonically decreases
B. Decreases and then increases
C. Remains constant
D. Increases and then decreases

Question 744

Air vessel fitted to a reciprocating pump

A. Increases the work done
B. Decreases the work done
C. Causes cavitation
D. Results in non-uniform discharge

Question 745

Hydraulic diameter for non-circular ducts is equal to __________ times the area of flow divided by the perimeter.

A. Two
B. Three
C. Four
D. Eight

Question 746

Momentum correction factor used in fluid flow problems accounts for the

A. Change in direction of flow
B. Change in total energy
C. Change in pressure
D. Non uniform direction of velocities at inlet & outlet sections

Question 747

What is the ratio of total kinetic energy of fluid passing per second to the value obtained on the basis of average velocity (for laminar flow through a circular pipe)?

A. 0.5
B. 1
C. 1.5
D. 2

Question 748

What is the ratio of the velocity at the axis of the pipe to the mean velocity of flow in case of pipe flow under viscous condition?

A. 0.5
B. 0.67
C. 1
D. 2

Question 749

Deformation drag, which is caused by widespread deformation of fluid around the immersed body

A. Occurs when NRe is very small
B. Is primarily a friction drag
C. Is independent of body length
D. Depends mainly on cross-sectional shape

Question 750

For an ideal fluid flow, Reynolds number is

A. 2100
B. 100
C. 0
D. ∞

Question 751

For ideally incompressible fluid, the Mach number will be

A. 1.5
B. 1
C. 0
D. 5

Question 752

Ratio of pressure and inertia force gives __________ number.

A. Weber
B. Mach
C. Euler
D. Froude

Question 753

Froude number is not a factor

A. For Reynolds number greater than 300
B. When there is no vortex formation
C. For unbaffled tank
D. None of these

Question 754

Froude number is the ratio of

A. Shear stress to gravitational stress
B. Drag stress to shear stress
C. Inertial stress to shear stress
D. Inertial stress to gravitational stress

Question 755

Applicability of Bernoulli's equation is limited to a/an __________ fluid, that does not exchange shaft work with the surroundings.

A. Incompressible
B. Non-viscous
C. Both A and B
D. Neither A nor B

Question 756

Disc compensators are provided in large diameter fuel gas carrying pipelines to

A. Keep the pipe in proper orientation
B. Make the pipe joint leak-proof
C. Account for contraction/expansion of pipe due to temperature changes of the surroundings
D. Account for the pressure variation side the pipeline

Question 757

During ageing of fluid carrying pipes, the

A. Pipe becomes smoother with use
B. Friction factor increases linearly with time
C. Absolute roughness decreases with time
D. Absolute roughness increases linearly with time

Question 758

A gas (density = 1.5 kg/m³ , viscosity = 2x 10⁻⁵ kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The pressure drop for another gas, with density of 1.5kg/m³and viscosity of 3 x 10⁻⁵kg/m.s flowing at 3 m/s will be

A. 8400 Pa/m
B. 12600 Pa/m
C. 18900 Pa/m
D. 16800 Pa/m

Question 759

Centrifugal pump can't be used to pump

A. Molten sodium (used as a coolant in Fast Breeder Reactor)
B. Moderately viscous vegetable oil used in soap industry
C. Thick molten soap at 80°C
D. None of the above

Question 760

The general relationship between speed N, head H, power P and discharge Q for a centrifugal pump is

A. Q∝N : H∝N² : P∝N³
B. Q∝N² : H∝N³ : P∝N
C. Q∝N : H∝N³ : P∝N²
D. Q∝N³ : H∝N : P∝N²

Question 761

The percentage slip in a reciprocating pump set is given by the % of (where, Q₁ = actual discharge Q₂ = theoretical discharge)

A. Q₁/Q₂
B. Q₂/Q₁
C. (Q₂ - Q₁)/Q₁
D. (Q₂ - Q₁)/Q₂

Question 762

What is the shear rate at the pipe wall, in case of laminar flow of Newtonion fluids in a pipe of diameter 'D' & length 'L' incurring a pressure drop 'Δp' with average velocity 'Vavg'?

A. D Δp/8L
B. D Δp/4L
C. 8 . Vavg/D
D. 4 . Vavg/D

Question 763

Gear pump

A. Is a positive displacement pump
B. Is a centrifugal pump
C. Is a non-positive displacement pump
D. Can be started with delivery valve closed

Question 764

The discharge through a venturimeter depends upon

A. Pressure drop only
B. Its orientation
C. Co-efficient of contraction only
D. None of these

Question 765

Surge tanks are provided in high pressure water pipelines to

A. Store a definte quantity ofwater all the time
B. Reduce the water hammer
C. Facilitate easy dismantling of pipeline for cleaning and maintenance
D. None of these

Question 766

Glass pipes can be joined by

A. Flanges
B. Welding
C. Soldering
D. Bell and spigot joint

Question 767

The maximum head that can be developed by a single impeller is __________ ft.

A. 25
B. 100
C. 250-300
D. 1000

Question 768

Diaphragm pumps are used to transport

A. Solids
B. Liquids
C. Fluids
D. Slurries

Question 769

Pick out the correct statement pertaining to the flow through a converging-diverging tube.

A. The value of Mach number is always unity at the throat
B. No shock wave develops in the tube when the Mach number at exit is greater than unity
C. Throughout the converging portion of the tube, the density increases in the downstream direction
D. None of these

Question 770

The discharge through a rectangular weir varies as

A. H1/2
B. H5/2
C. H2/5
D. H3/2

Question 771

The boundary layer thickness at a given section along a flat plate __________ with increasing Reynold's number.

A. Increases
B. Decreases
C. Remains same
D. May increase or decrease

Question 772

The line of action of the buoyant force passes through the centre of gravity of the

A. Submerged body
B. Displaced volume of the fluid
C. Volume of fluid vertically above the body
D. Horizontal projection of the body

Question 773

The ratio of the depth of flow to the diameter of the channel for maximum discharge in a circular channel in open channel flow is

A. 0.1
B. 0.55
C. 0.95
D. 1.85

Question 774

In case of a rotameter, the density of the float material is __________ that of the liquid it replaces.

A. More than
B. Less than
C. Equal to
D. Either A or B

Question 775

In Newton's law range, the terminal velocity of a solid spherical particle falling through a stationary fluid mass varies as the __________ of its diameter.

A. Inverse
B. Square root
C. Second power
D. First power

Question 776

Which of the following has the maximum compression ratio?

A. Blower
B. Compressor
C. Vacuum pump
D. Fan

Question 777

Stoke's law is valid, when the particle Reynolds number is

A. < 1
B. > 1
C. < 5
D. None of these

Question 778

Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles) no change in the

A. Drag on particles
B. Drag on coloumn walls
C. Bed height
D. Bed voidage