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Environmental Engineering MCQ Questions & Answers

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

Question 1

Bag filter design is predominantly dependent on gas temperature, as it affects the gas density & viscosity and the selection of filtering material. The pressure drop in a bag filter is

A. inversely proportional to viscosity of gas.
B. proportional to the viscosity & density of the gas.
C. proportional to the pressure of the gas.
D. both (b) and (c).

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Question 2

Maximum allowable concentration of CO2 in air for safe working is __________ ppm (parts per million).

A. 50
B. 1000
C. 2000
D. 5000

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Question 3

_________ is the simplest equipment used for collection of solid particulates.

A. Inertial separators
B. Filters
C. Settling chamber
D. Cyclones

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Question 4

Iron & manganese present as pollutant in water can not be removed by

A. ion exchange process.
B. oxidation followed by settling & filtration.
C. lime soda process or manganese zeolite process.
D. chlorination.

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Question 5

Noise level heard at a distance of about 100 metres from a jet engine with after burner is about __________ decibels.

A. 120
B. 140
C. 170
D. 200

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Question 6

Scale formation in boiler is controlled by

A. preheating of feed water.
B. reduction in hardness, silica & alumina in feed water.
C. keeping the pH value of feed water just below 7.
D. eliminating H2S in feed water.

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Question 7

Which is a secondary air pollutant ?

A. Photochemical smog
B. Sulphur dioxide
C. Nitrogen dioxide
D. Dust particles

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Question 8

Inhalation of lead compounds present in the automobile exhausts (using leaded petrol) causes

A. blood poisoning.
B. anaemia.
C. nervous system disorder.
D. all (a), (b) and (c).

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Question 9

Polluted water having low BOD are most economically treated in

A. sedimentation tanks
B. oxidation ponds
C. sludge digester
D. clarifier

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Question 10

Main pollutants released from iron & steel industry is

A. CO, CO2 & SO2.
B. H2S, NO & SO3.
C. CO2, H2S & NO2.
D. SO3, NO2 & CO2.

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Question 11

The ratio of oxygen available to the oxygen required for stabilisation of sewage is called the

A. bacterial stability factor.
B. relative stability.
C. biological oxygen demand (BOD).
D. oxygen ion concentration.

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Question 12

Which of the following is the common pollutant emitted from metallurgical smelters, thermal power plant and cement plants ?

A. NOx
B. Hg
C. SO2
D. F

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Question 13

TLV of mercury in potable (drinking) water is about __________ ppm.

A. 0.001
B. 0.1
C. 1
D. 5

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Question 14

Fluorosis (a bone disease) is caused by the presence of high concentration of __________ in atmospheric air.

A. hydrocarbons
B. hydrogen flouride
C. hydrogen sulphides
D. nitrogen dioxide

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Question 15

In water chemical treatment plant, use of chloramines ensures

A. disinfection.
B. taste & odour control.
C. weed control in reservoirs.
D. removal of permanent hardness.

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Question 16

Tolerable limit of nitrogen oxides in air is __________ ppm.

A. 0.1
B. 1
C. 5
D. 25

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Question 17

The commonest form of iron & manganese found in ground water as pollutant is in the form of their

A. carbonates
B. bi-carbonates
C. chlorides
D. sulphides

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Question 18

Hydrogen Peroxide is generated from:

A. Photochemical smog products
B. Explosive manufacturing industry
C. Automobile exhausts
D. Thermal power plants

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Question 19

Which is the best and the most effective method for the removal of organic contaminant present in the polluted water in very small quantity (say < 200 mg/litre)?

A. Lagooning
B. Activated carbon adsorption
C. Biological oxidation pond
D. Chemical coagulation

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Question 20

Most of the atmospheric air pollutants are present in large quantity in

A. stratosphere
B. thermosphere
C. trophosphere
D. mesosphere

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Question 21

Presence of excess flourine in water causes

A. dental cavity
B. tooth decay
C. fluorosis
D. respiratory disease

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Question 22

To test turbidity of polluted water in the field, _________ is used.

A. Baylis Turbidimeter
B. Jackson Turbidimeter
C. Turbidity tube
D. Turbidity rod

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Question 23

_________ is a raw material sent to and processed in a waste recycling plant.

A. Recyclant
B. Nodules
C. Particulars
D. Recyclate

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Question 24

Aerobic biological oxidation ponds used for the purification of polluted water

A. destroys/removes pathogen from the sewage.
B. is not very effective for nonbiodegradable substances (e.g. ABS) containing effluents.
C. destroys/removes pathogen much more effectively if the sewage is chlorinated.
D. all (a), (b) & (c).

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Question 25

The main pollutant in waste water discharged from a petroleum refinery is oil (both in free and emulsified form). Free oil is removed by

A. biological oxygen pond.
B. aerated lagoons.
C. trickling filters.
D. gravity separator having oil skimming devices.

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Question 26

Aerodynamic noise resulting from turbulent gas flow is the most prevalent source of valve noise in fluid ilow control. It is caused due to

A. Reynold stresses
B. shear forces
C. both (a) & (b)
D. neither (a) nor (b)

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Question 27

Pollution cases can be classified into _________ types.

A. 4
B. 2
C. 5
D. 6

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Question 28

Which of the following is the most detrimental for water used in high pressure boiler ?

A. Silica
B. Turbidity
C. Phenol
D. Dissolved oxygen

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Question 29

Pick out the wrong statement.

A. The concentric atmosphere layer just above troposphere is called stratosphere, which is rich in ozone.
B. Mesosphere is characterised by very low atmospheric pressure and low temperature.
C. Troposhere is a dusty zone containing water vapor and clouds.
D. The radio waves used in the long distance radio communication are reflected back to earth by stratosphere.

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Question 30

Coal washing waste water containing about 3% suspended solids (comprising of clay, slate, stone etc.) is treated for solid particles removal

A. by chemical coagulation.
B. in sedimentation tanks equipped with mechanical scrapper.
C. in vacuum filter.
D. in clarifiers.

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Question 31

Persons working in cement plants and limestone quarries are more prone to disease like

A. cancer
B. asthma
C. silicosis
D. flourosis (bone disease)

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Question 32

Inhalation of lead compounds present in automobile exhaust (using leaded petrol) causes

A. blood poisoning.
B. anaemia.
C. nervous system disorder.
D. all (a), (b) & (c).

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Question 33

TLV of ozone (O3) and phosgene (COCl2) in air is __________ ppm.

A. 0.1
B. 25
C. 100
D. 1000

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Question 34

Siderosis is a disease caused by the inhalation of __________ dust.

A. coal
B. silica
C. iron
D. none of these

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Question 35

What are the main constituents of the environmental cycles?

A. Water cycle and food cycle
B. Water cycle and nutrient cycle
C. Nutrient cycle
D. Water cycle and air cycle

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Question 36

H2S present in gaseous stream can be removed by adsorption on

A. silica gel
B. active carbon
C. bog iron
D. limestone powder

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Question 37

Turbidity of water is an indication of the presence of

A. suspended inorganic matter
B. dissolved solids
C. floating solids
D. dissolved gases

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Question 38

Ionisation potential employed in the industrial electrostatic precipitator is of the order of

A. 30 to 70 kV DC
B. 30 to 70 kV AC
C. 230 V AC
D. 230 V DC

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Question 39

The living environment, the biosphere consists of __________ components.

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

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Question 40

Particulates (< 1μm size) remaining suspended in air indefinitely and transported by wind currents are called

A. fumes
B. mists
C. smoke
D. aerosols

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Question 41

Failures within hydrosphere in oxygen cycle can result in the development of:

A. Hyperoxic zones
B. Hypoxic zones
C. Hydrolic zones
D. Hydroxic zones

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Question 42

Tri-sodium phosphate is used in boiler water treatment to reduce

A. turbidity
B. caustic embrittlement
C. suspended silica
D. dissolved oxygen

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Question 43

The widest explosive limit is of __________ , thereby making it the most explosive gas.

A. acetylene
B. petrol vapor
C. hydrogen
D. carbon monoxide

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Question 44

Phenolic water generated in coke ovens & by-product plant attached to an integrated steel plant containing phenol in concentration of less than 100 mg/litre can be removed by

A. chlorination
B. treating in biological oxygen pond
C. chemical coagulation
D. none of these

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Question 45

When some chemical is mixed with water, _________ is formed.

A. Solution
B. Floc
C. Bubbles
D. Foam

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Question 46

During which of the following operating conditions of an automobile, carbon monoxide content in the exhaust gas is maximum ?

A. Idle running
B. Acceleration
C. Cruising
D. Deaccelaration

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Question 47

'Pneumoconiosis' is a disease caused by the inhalation of __________ dust.

A. coal
B. uranium ore
C. iron ore
D. lime

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Question 48

Which of the below leads to disturbance of nitrogen fixation in the soil?

A. Urban waste
B. Fertilizers
C. Pesticides
D. Industrial effluents

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Question 49

Exposure to chemicals having carcinogenic properties cause

A. dermatitis (skin disorder)
B. cancer
C. asphyxiation (suffocation)
D. asthma

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Question 50

Which of the following pollutants is not emitted during volcanic eruptions ?

A. SO2
B. H2S
D. hydrocarbons

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Question 51

Suspended solid present in the waste water generated in blast furnace gas cooling and cleaning plant is removed by

A. biological oxygen pond.
B. radial settling tank (thickener) using coagulant (lime & ferrous sulphate).
C. lagoons.
D. filtration.

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Question 52

Threshold Limit Value (TLV) is the maximum allowable concentration (i.e. safe limit) of pollutants in air. Safe limit for SO2 in air is __________ ppm.

A. 5
B. 500
C. 1000
D. 2000

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Question 53

Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by

A. natural aeration of water stream.
B. photosynthetic action of algae.
C. both (a) & (b).
D. neither (a) nor (b).

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Question 54

Which of the following dust collection equipments is the least efficient (for sub-micronic particles) ?

A. Dust catcher (gravity type)
B. Cyclone separator
C. Bag filter
D. Hollow wet scrubber

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Question 55

The presence of gas in water is indicated by:

A. Fizzing sound
B. Foam
C. Bubbles
D. Colour change

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Question 56

Exposure to small amount of __________ results in high blood pressure & heart disease in human beings.

A. hydrogen sulphide
B. mercury
C. cadmium
D. asbestos

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Question 57

Pick out the wrong statement.

A. Caustic embrittlement of boiler's metallic parts is caused by high concentration of caustic soda in boiler feed water.
B. Cooling and freezing of water kills the bacteria present in it.
C. With increasing boiler operating pressure of steam, the maximum allowable concentration of silica in feed water goes on decreasing.
D. Dissolved oxygen content in high pressure boiler feed water should be nil.

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Question 58

Smoke is produced due to

A. insufficient supply of combustion air and insufficient time for combustion.
B. poor quality of fuel and improper mixing of fuel & combustion air.
C. poor design & overloading of furnace.
D. all (a), (b) and (c).

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Question 59

In the method of trenching, the size of the trench may be:

A. 12 x 5 x 2m
B. 15 x 5 x 3m
C. 12 x 3 x 2m
D. 15 x 5 x 5m

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Question 60

Operating principle of cyclone separator is based on the action of __________ dust particles.

A. diffusion of
B. centrifugal force on
C. gravitational force on
D. electrostatic force on

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Question 61

80% less than 200 mesh size particles are called

A. smoke
B. powder
C. grit
D. aggregates

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Question 62

Dust collection efficiency of a cyclone separator depends upon its

A. diameter.
B. inlet gas velocity.
C. overall height.
D. all (a), (b) & (c).

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