Agitation and Aeration MCQs

Welcome to our comprehensive collection of Multiple Choice Questions (MCQs) on Agitation and Aeration, a fundamental topic in the field of Biochemical Engineering. Whether you're preparing for competitive exams, honing your problem-solving skills, or simply looking to enhance your abilities in this field, our Agitation and Aeration MCQs are designed to help you grasp the core concepts and excel in solving problems.

In this section, you'll find a wide range of Agitation and Aeration mcq questions that explore various aspects of Agitation and Aeration problems. Each MCQ is crafted to challenge your understanding of Agitation and Aeration principles, enabling you to refine your problem-solving techniques. Whether you're a student aiming to ace Biochemical Engineering tests, a job seeker preparing for interviews, or someone simply interested in sharpening their skills, our Agitation and Aeration MCQs are your pathway to success in mastering this essential Biochemical Engineering topic.

Note: Each of the following question comes with multiple answer choices. Select the most appropriate option and test your understanding of Agitation and Aeration. You can click on an option to test your knowledge before viewing the solution for a MCQ. Happy learning!

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Agitation and Aeration MCQs | Page 6 of 11

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Q51.
Larger propellers turn at the speed of

a.

20 to 150 rpm

b.

150 to 300 rpm

c.

400 to 800 rpm

d.

1150 rpm

Discuss
Answer: (c).400 to 800 rpm
Q52.
A microbial population in a suspension culture will only be limited by oxygen availability if the dissolved oxygen

a.

concentration is less than the critical concentration

b.

concentration is greater than the critical concentration

c.

levels are greater than the saturation concentration of oxygen

d.

levels are equal to saturation oxygen level

Discuss
Answer: (a).concentration is less than the critical concentration
Q53.
Which of the following model holds correct for the two-film theory? (where KL is the mass transfer coefficient, DAB diffusivity and Zf film thickness)

a.

KL = DAB/Zf

b.

KL = DAB

c.

KL = Zf/DAB

d.

KL = DAB.Zf

Discuss
Answer: (a).KL = DAB/Zf
Q54.
Froude number is avoided in calculation of power requirements for low viscosity liquid mixing systems when

a.

baffled systems are used

b.

Reynolds number is less than 300

c.

both (a)and(b)

d.

none of these

Discuss
Answer: (c).both (a)and(b)
Q55.
A fermentation system has a KLa of 3 s­¹ and a C0* of 5 ppm of O₂. If the bulk liquid is completely depleted of oxygen, then the oxygen transfer rate will be equal to

a.

zero

b.

15 mg.l­¹.s­¹

c.

10 mg.l­¹.s­¹

d.

5 mg.l­¹.s­¹

Discuss
Answer: (b).15 mg.l­¹.s­¹
Q56.
During fermentation, the saturation concentration of oxygen was reduced from 7 ppm. to 1 ppm. Which one of the following conclusions can be drawn?

a.

Microbial growth is oxygen limited since the oxygen concentration is lesser than the saturation concentration

b.

Microbial growth is not oxygen limited since the oxygen concentration is lesser than the saturation concentration

c.

Experimental error leads to the reduction

d.

No conclusion can be drawn

Discuss
Answer: (d).No conclusion can be drawn
Q57.
If the stirrer speed is too slow, bubbles will accumulate and coalescese under the impeller. This phenomenon is known as a

a.

coalesced impeller

b.

flooded impeller

c.

river impeller

d.

dry impeller

Discuss
Answer: (b).flooded impeller
Q58.
The maximum solubility of the alkane in the medium is 5 ppm. If the actual dissolved concentration of the alkane in the medium is 1 ppm. what conclusion may be drawn?

a.

The growth rate is limited by the rate of mass transfer of the alkane into the fermentation medium

b.

The growth rate is limited by the intrinsic kinetic properties of the cells and not by mass transfer

c.

The growth rate is neither mass transfer nor kinetically limited

d.

No conclusion on the growth rate can be withdrawn

Discuss
Answer: (d).No conclusion on the growth rate can be withdrawn
Q59.
Reynolds (Rei) number for the impeller is given by (where Di, stirrer diameter; N, stirrer speed, ρ, density of fluid and μ, viscosity of fluid)

a.

DiVρ/μ

b.

Di2Nρ/μ

c.

Di2Vρ/μ

d.

DiNρ /μ

Discuss
Answer: (b).Di2Nρ/μ
Q60.
The advantage of axial flow impellers over radial flow impellers is that axial flow impellers

a.

provide better lift of solids

b.

provide high shear conditions

c.

provide low shear conditions

d.

are cheaper to build

Discuss
Answer: (a).provide better lift of solids
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