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 4 of 11

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Q31.
The average concentration of oxygen in the boundary layers surrounding the bubbles (Co*) in a reactor is normally determined by

a.

ultra-small dissolved oxygen probes

b.

laser based photographic systems

c.

measuring the steady state concentration of oxygen in the bulk liquid prior to inoculation of the reactor

d.

measuring the steady state concentration of oxygen in the bulk liquid after inoculation of the reactor

Discuss
Answer: (c).measuring the steady state concentration of oxygen in the bulk liquid prior to inoculation of the reactor
Q32.
Why vortexing is undesirable in the agitation of biological systems?

a.

The collision between the cells, impeller and air bubbles will lead to cell damage

b.

Poor mixing despite the use of high stirrer speeds

c.

Mixing will not be in the turbulent region

d.

All of the above

Discuss
Answer: (d).All of the above
Q33.
What is the ratio of depth of liquid in vessel to the diameter of tank (H:Dt)?

a.

1 : 1

b.

2 : 1

c.

4 : 1

d.

none of these

Discuss
Answer: (a).1 : 1
Q34.
The effect of increasing the stirrer speed in an unbaffled stirred tank reactor is that

a.

a small increase in stirrer speed will cause the liquid to enter the turbulent flow regime

b.

as the stirrer speed increases, the liquid will continue to circulate and then become turbulent

c.

as the stirrer speed increases, the liquid will continue to circulate. Eventually a vortex will form.

d.

A vortex will form at low stirrer speeds. As the stirrer speed increases the liquid will start to circulate

Discuss
Answer: (c).as the stirrer speed increases, the liquid will continue to circulate. Eventually a vortex will form.
Q35.
Turbulent flow range of mixing speed is obtained for

a.

Rei<10

b.

10<Rei<10⁴

c.

Rei>10⁴

d.

None of these

Discuss
Answer: (c).Rei>10⁴
Q36.
For laminar flow, Reynolds number is correlated with power number as (where K, a constant which depends on the container geometry and shape of stirrer; Rei is Reynolds number for agitator; Di, stirrer diameter and N, stirrer speed)

a.

Np = K(Rei)­¹

b.

Np = N2Di(Rei)­¹

c.

Np = K(Rei)

d.

Np = KNDi(Rei)­²

Discuss
Answer: (a).Np = K(Rei)­¹
Q37.
For turbulent flow, Reynolds number is correlated with power number as (where K, a constant which depends on the container geometry and shape of stirrer; Rei, is Reynolds number for agitator; Di, stirrer diameter and N, stirrer speed)

a.

Np = K(Rei)­¹

b.

Np = N2Di(Rei)­¹

c.

Np = K

d.

Can't be correlated

Discuss
Answer: (c).Np = K
Q38.
In a bioreactor, if at a particular time the oxygen transfer rate is 23 kg.h­¹, then the oxygen uptake will be

a.

23 kg.h­¹

b.

less than 23 kg.h­¹

c.

greater than 23 kg.h­¹

d.

2.3 kg.h­¹

Discuss
Answer: (a).23 kg.h­¹
Q39.
In a two-phase system where the continuous phase remains in place, the gas hold up can be expressed as (where Vs and Vt are the superficial gas velocity and bubble rise velocity)

a.

H = Vs/(Vs-Vt)

b.

H = Vs/(Vs+ Vt)

c.

H = Vs/(Vs.Vt)

d.

H = (Vs+Vt)/Vs

Discuss
Answer: (b).H = Vs/(Vs+ Vt)
Q40.
What is the effect of the concentration of dissolved salts and sugars on the oxygen transfer rate?

a.

The saturation concentration of oxygen in the medium decreases with the concentration of dissolved salts and sugars, leading to a lower oxygen transfer rate

b.

The KLa of the medium decreases with the concentration of dissolved salts and sugars, leading to a lower oxygen transfer rate

c.

The KLa of the medium increases with the concentration of dissolved salts and sugars, leading to a lower oxygen transfer rate

d.

None of the above

Discuss
Answer: (a).The saturation concentration of oxygen in the medium decreases with the concentration of dissolved salts and sugars, leading to a lower oxygen transfer rate
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