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Q1. | The collection efficiency by diffusion increases with |

A. | decreasing particle size [Wrong Answer] |

B. | decreasing air velocity [Wrong Answer] |

C. | both (a) and (b) [Correct Answer] |

D. | increasing particle size [Wrong Answer] |

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Explanation:-
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**Also Read Similar Questions Below :**

⇒ Sterilization can be carried out by

heat

radiation

chemical agents

all of these

⇒ The value of K

increases with increase in air velocity

decreases with increase in air velocity

increases to an optimum with increase in air velocity and decreases on further increase of air velocity

none of these

⇒ The specific death rate of an organism can be expressed as

ln 2/

*D*

*D*/ln2

*D*.ln2

2.0.3/ln2

⇒ The del factor (Δ) increases as the final number of cells

decreases

increases

zero

constant

⇒ The mechanism of air filtration in fibrous filter is

electrostatic attraction

impaction

interception

all of these

⇒ Typical aeration rates for aerobic fermentation are

0 - 0.5 vvm

0.5 - 1.0 vvm

1.0 - 1.5 vvm

1.5 - 2.0 vvm

⇒ The deviation from ideal plug flow due to axial mixing can be described by the

dispersion model

Langmuir model

Friedlander model

Pasceri model

⇒ The overall del factor (Δ) may be represented as

Δ

_{overall}= Δ

_{heating}+ Δ

_{holding}- Δ

_{cooling}

Δ

_{overall}= Δ

_{heating}+ Δ

_{holding}+ Δ

_{cooling}

Δ

_{overall}= Δ

_{heating}- Δ

_{holding}+ Δ

_{cooling}

Δ

_{overall}= Δ

_{heating}- Δ

_{holding}- Δ

_{cooling}

⇒ The collection efficiency by impaction increases with

increasing particle diameter

increasing air flow velocity

both (a) and (b)

increasing particle size

⇒ 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

*V*is undisturbed fluid velocity)

_{0}*V*=

*V*/(1-α)

_{0}*V-V*= 1 - α

_{0}*V*=

*V*(1 - α)

_{0}*V*=

*V*/(1 + α)

_{0}⇒ For laminar flow of Newtonian fluid through a smooth round pipe, the ratio of average fluid velocity to the maximum velocity is

0.5

0.75

0.87

0.37

⇒ Glass fibers are favorable as a filter medium because they give a

lower pressure drop and are less liable to wetting or combustion

more pressure drop and are less liable to wetting or combustion

lower pressure drop and are more liable to wetting or combustion

more pressure drop and are more liable to wetting or combustion

⇒ The reduction of number of cells from 10

^{10}to one will result into the del factor (Δ) of

1

10

23

10

^{3 }

⇒ 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

*J*is flux component '

_{n}*n*',

*c*is concentration of'

_{n}*n*')

*J*= -

_{n}*dc*/

_{n}*dx*

*J*=

_{n}*dc*/

_{n}*dx*

*J*= -

_{n}*D dc*/

_{n}*dx*

*J*=

_{n}*D dc*/

_{n}*dx*

⇒ The typical size of particles collected by diffusion mechanism is

<0.25μm

<0.5μm

<0.75μm

<1μm

⇒ The heat conduction in dry air is

less rapid than in steam

more rapid than in steam

similar to steam

none of these

⇒ For the turbulent flow, the dispersion coefficient is correlated as a function of

Reynolds number

Sherwood number

Schmidt number

Grashof number

⇒ The relationship between the del factor, temperature and time is given as

Δ = A.t. e

^{-E/RT}

Δ = 1/(A.t. e

^{-E/RT})

Δ = A.t. e

^{E/RT}

Δ = A.t.T

⇒ The destruction of microorganisms by steam may be described as

first order chemical reaction

zero order chemical reaction

second order chemical reaction

none of these

⇒ The sterilization method depends

nature of additive

volume and feed rate

both (a) and (b)

none of these

⇒ The mechanical means of accomplishing sterilization of fermentation media/equipment is

ultrasonic

radiation

chemical agents

none of these

⇒ The collection efficiency by diffusion increases with

decreasing particle size

decreasing air velocity

both (a) and (b)

increasing particle size

⇒ The interception efficiency can be expressed as (where

*d*is the particle diameter and

_{p}*D*cylindrical collection diameter)

_{c}*d*/

_{p}*D*

_{c}*d*x

_{p}*D*

_{c}*d*/

_{p}*D*x 100

_{c}*d*

_{p}*D*/100

_{c}⇒ The radius of the filter with a depth of 14 cm required for a volumetric airflow rate of 10 m

^{3}/min is approximately

1.6 m

0.6 m

3

6 m

⇒ Model proposed by the Friedlander, correlating the air filtration efficiency by impaction can be expressed as (where

*N*is the Stokes number)

_{St}η

_{imp}= 0.075

*N*

_{St}^{1.2}

η

_{imp }= 0.75

*N*

_{St}^{1.2}

η

_{imp}= 0.25

*N*

_{St}^{1.2}

η

_{imp}= 0.025

*N*

_{St}^{1.2 }

⇒ The highest temperature which appears to be feasible for batch sterilization is

121°C

100°C

105°C

130°C

⇒ The heated medium passes through a holding section, which is usually maintained in

adiabatic conditions

isothermal conditions

isotropic conditions

isobaric conditions

⇒ The

*X*value for a filtration system is

_{90}the time required to reduce microbial population by 90%

the time required to traverse survivor curve by one log cycle.

the depth required to reduce population by 90%

the depth of the filter required to reduce population by 99%

⇒ The K used in the equation for

*X*

_{10}=2.303/K depends upon

nature of the filter material

linear velocity of the air passing through filter

both (a) and (b)

thickness of the filter

⇒ The moist heat is more effective than the dry heat because the intrinsic heat resistance of vegetative cells is greatly

increased in a dry state

decreased in a dry state

increased in a wet state

decreased in a wet state