Sterilization MCQs : This section focuses on the "Sterilization". These Multiple Choice Questions (MCQs) should be practiced to improve the Sterilization skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
The sterilization method depends
A. nature of additive
B. volume and feed rate
C. Both A and B
D. None of the above
Question 2
The specific death rate of an organism can be expressed as
A. ln 2/D
B. D/ln2
C. D.ln2
D. 2.0.3/ln2
Question 3
The interception efficiency can be expressed as (where dp is the particle diameter and Dc cylindrical collection diameter)
A. dp/Dc
B. dp x Dc
C. dp/Dc x 100
D. dpDc/100
Question 4
The relationship between the del factor, temperature and time is given as
A. Δ = A.t. e^-E/RT
B. Δ = 1/(A.t. e^-E/RT)
C. Δ = A.t. e^E/RT
D. Δ = A.t.T
Question 5
The del factor (Δ) increases as the final number of cells
A. decreases
B. increases
C. zero
D. constant
Question 6
The overall del factor (Δ) may be represented as
A. Δoverall = Δheating + Δholding- Δcooling
B. Δoverall = Δheating + Δholding+ Δcooling
C. Δoverall = Δheating - Δholding+ Δcooling
D. Δoverall = Δheating - Δholding- Δcooling
Question 7
The filter material used for air filtration system is/are
A. glass wool
B. glass fibre
C. norite
D. All of the above
Question 8
The deviation from ideal plug flow due to axial mixing can be described by the
A. dispersion model
B. Langmuir model
C. Friedlander model
D. Pasceri model
Question 9
The collection efficiency by diffusion increases with
A. decreasing particle size
B. decreasing air velocity
C. Both A and B
D. increasing particle size
Question 10
Glass fibers are favorable as a filter medium because they give a
A. lower pressure drop and are less liable to wetting or combustion
B. more pressure drop and are less liable to wetting or combustion
C. lower pressure drop and are more liable to wetting or combustion
D. more pressure drop and are more liable to wetting or combustion
Question 11
The collection efficiency by interception increases with the
A. increasing particle diameter
B. increasing air flow velocity
C. Both A and B
D. increasing particle size
Question 12
For indirect heating, the plate and frame heat exchanger is generally more effective than the shell and tube heat transfer due to its
A. larger heat transfer area
B. smaller heat transfer area
C. lesser cost
D. more number of plates
Question 13
The mechanism of air filtration in fibrous filter is
A. electrostatic attraction
B. impaction
C. interception
D. All of the above
Question 14
If the packing density (α) is defined as the volume of the fiber unit volume of filter bed, the velocity within the filter void space is equal to (where V is velocity in fluid void space and V0 is undisturbed fluid velocity)
A. V = V0/(1-α)
B. V-V0 = 1 - α
C. V = V0(1 - α)
D. V = V0/(1 + α)
Question 15
For the turbulent flow, the dispersion coefficient is correlated as a function of
A. Reynolds number
B. Sherwood number
C. Schmidt number
D. Grashof number
Question 16
In sterilization process, spore of which of the following organism is considered as control?
A. Bacillus subtilis
B. Clostridium botulinum
C. Bacillus stearothermophilus
D. Aspergillus niger
Question 17
Analogus to the molecular diffusion, the x-directional flux of microorganisms suspended in a medium due to the axial mixing can be represented as (where Jn is flux component 'n', cn is concentration of'n')
A. Jn = -dcn/dx
B. Jn = dcn/dx
C. Jn = -D dcn/dx
D. Jn = D dcn/dx
Question 18
The typical size of particles collected by diffusion mechanism is
A. <0.25μm
B. <0.5μm
C. <0.75μm
D. <1μm
Question 19
The X90 value for a filtration system is
A. the time required to reduce microbial population by 90%
B. the time required to traverse survivor curve by one log cycle.
C. the depth required to reduce population by 90%
D. the depth of the filter required to reduce population by 99%
Question 20
The value of K
A. increases with increase in air velocity
B. decreases with increase in air velocity
C. increases to an optimum with increase in air velocity and decreases on further increase of air velocity
D. None of the above
Question 21
Model proposed by the Friedlander, correlating the air filtration efficiency by impaction can be expressed as (where NSt is the Stokes number)
A. ηimp = 0.075NSt^1.2
B. ηimp = 0.75NSt^1.2
C. ηimp = 0.25NSt^1.2
D. ηimp = 0.025NSt^1.2
Question 22
The collection efficiency by impaction increases with
A. increasing particle diameter
B. increasing air flow velocity
C. Both A and B
D. increasing particle size
Question 23
The efficiency of fibrous filter by combined mechanism is given by(where ηimp,ηint,ηdif are the efficiencies by impaction, interception and diffusion respectively)
A. 1 - ηimpηintηdif
B. 1 - (1 - ηimp)(1 - ηint)( 1 - ηdif)
C. 1 - ( ηimpηint/ηdif)
D. None of the above
Question 24
The heat conduction in dry air is
A. less rapid than in steam
B. more rapid than in steam
C. similar to steam
D. None of the above
Question 25
For laminar flow of Newtonian fluid through a smooth round pipe, the ratio of average fluid velocity to the maximum velocity is
A. 0.5
B. 0.75
C. 0.87
D. 0.37
Question 26
Model proposed by the Friedlander, correlating the air filtration efficiency by impaction can be expressed as (where NSt is the Stokes number)
A. ηimp = 0.075NSt1.2
B. ηimp = 0.75NSt1.2
C. ηimp = 0.25NSt1.2
D. ηimp = 0.025NSt1.2
Question 27
Sterilization can be carried out by
A. heat
B. radiation
C. chemical agents
D. all of these
Question 28
The collection efficiency by diffusion increases with
A. decreasing particle size
B. decreasing air velocity
C. both (a) and (b)
D. increasing particle size
Question 29
The collection efficiency by impaction increases with
A. increasing particle diameter
B. increasing air flow velocity
C. both (a) and (b)
D. increasing particle size
Question 30
The collection efficiency by interception increases with the
A. increasing particle diameter
B. increasing air flow velocity
C. both (a) and (b)
D. increasing particle size
Question 31
The collection efficiency by the inertial impaction mechanism is the function of
A. Stokes and Reynolds number
B. Stokes and Schmidt number
C. Grashoff and Reynolds number
D. Stokes and Grashof number
Question 32
The destruction of microorganisms by steam may be described as
A. first order chemical reaction
B. zero order chemical reaction
C. second order chemical reaction
D. none of these
Question 33
The heat conduction in dry air is
A. less rapid than in steam
B. more rapid than in steam
C. similar to steam
D. none of these
Question 34
The heated medium passes through a holding section, which is usually maintained in
A. adiabatic conditions
B. isothermal conditions
C. isotropic conditions
D. isobaric conditions
Question 35
The highest temperature which appears to be feasible for batch sterilization is
A. 121°C
B. 100°C
C. 105°C
D. 130°C
Question 36
The K used in the equation for X10=2.303/K depends upon
A. nature of the filter material
B. linear velocity of the air passing through filter
C. both (a) and (b)
D. thickness of the filter
Question 37
The mechanical means of accomplishing sterilization of fermentation media/equipment is
A. ultrasonic
B. radiation
C. chemical agents
D. none of these
Question 38
The mechanism of air filtration in fibrous filter is
A. electrostatic attraction
B. impaction
C. interception
D. all of these
Question 39
The moist heat is more effective than the dry heat because the intrinsic heat resistance of vegetative cells is greatly
A. increased in a dry state
B. decreased in a dry state
C. increased in a wet state
D. decreased in a wet state
Question 40
The radius of the filter with a depth of 14 cm required for a volumetric airflow rate of 10 m3/min is approximately
A. 1.6 m
B. 0.6 m
C. 3
D. 6 m
Question 41
The reduction of number of cells from 1010 to one will result into the del factor (Δ) of
A. 1
B. 10
C. 23
D. 103
Question 42
The relationship between the del factor, temperature and time is given as
A. Δ = A.t. e-E/RT
B. Δ = 1/(A.t. e-E/RT)
C. Δ = A.t. eE/RT
D. Δ = A.t.T
Question 43
The sterilization method depends
A. nature of additive
B. volume and feed rate
C. both (a) and (b)
D. none of these
Question 44
The value of K
A. increases with increase in air velocity
B. decreases with increase in air velocity
C. increases to an optimum with increase in air velocity and decreases on further increase of air velocity
D. none of these
Question 45
Typical aeration rates for aerobic fermentation are
A. 0 - 0.5 vvm
B. 0.5 - 1.0 vvm
C. 1.0 - 1.5 vvm
D. 1.5 - 2.0 vvm
Question 46
_______ is the quickest way to sterilize solutions without heating.
A. Filtration
B. Chemical method of sterilization
C. Steam Sterilization
D. Chlorine dioxide gas
Question 47
_______ is used for sterilizing metallic devices like needles, scalpels.
A. Flaming
B. Incineration
C. Hot air oven
D. Steam
Question 48
____________ is used for sterilizing inoculating loops.
A. Flaming
B. Incineration
C. Hot air oven
D. Steam
Question 49
Does sterilization kill viruses?
A. TRUE
B. FALSE
Question 50
The sterilization of ________ is generally carried out by retorts.
A. low carbohydrate foods
B. low acid foods
C. high acid foods
D. medium acid foods
Question 51
Where should a sterilization indicator placed in an autoclave?
A. At the center
B. Close to lid of the autoclave
C. Sides of the autoclave
D. Anywhere inside the autoclave
Question 52
Which of the following is target microbe in commercial sterilization?
A. Pseudomonas aeruginosa
B. Bacillus anthracis
C. Salmonella typhi
D. Clostridium botulinum
Question 53
Who developed steam sterilizer?
A. Louis Pasteur
B. Charles Chamberland
C. Nicolas Appert
D. Clarence Birdseye