Food Engineering Questions and Answers – Unit Operations – Diffusion and Mass Transfer-2

This set of Food Engineering quiz focuses on “Diffusion and Mass Transfer-2”.

1. Statement 1: Concentration is a product of diffusivity and solubility.
Statement 2: Permeability coefficient in case of food packaging can be written as product of partial pressure and solubility using Henry’s law.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer

Answer: b
Explanation: Permeability coefficient is a product of diffusivity and solubility. Concentration in case of food packaging can be written as product of partial pressure and solubility using Henry’s law.

2. The existence of a thick constant film between two phases is a proposal by which of the following theories?
a) Film theory
b) Penetration theory
c) Surface renewal theory
d) All of the mentioned
View Answer

Answer: a
Explanation: The existence of a thick constant film between two phases is a proposal by the Film theory.

3. Statement 1: Penetration theory states that mass transfer coefficient is directly proportional to diffusivity coefficient which was later proved wrong.
Statement 2: Penetration theory states that mass transfer is based on unsteady mass transfer.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer

Answer: d
Explanation: Film theory states that mass transfer coefficient is directly proportional to diffusivity coefficient which was later proved wrong.
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4. Statement 1: In film theory, mass transfer coefficient is proportional to D1/2
Statement 2: Penetration theory states that all elements are exposed at the same time which is unrealistic.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer

Answer: d
Explanation: In Penetration theory, mass transfer coefficient is proportional to D1/2 Penetration theory.

5. Which theory proposes that the film is continuously getting renewed and replaced by the bulk liquid?
a) Film theory
b) Penetration theory
c) Surface renewal theory
d) None of the mentioned
View Answer

Answer: c
Explanation: Surface renewal theory proposes that the film is continuously getting renewed and replaced by the bulk liquid.
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6. Statement 1: KLa is measured together and not separately.
a) True
b) False
View Answer

Answer: a
Explanation: KLa is measured together and not separately.

7. Which of the following is not a measuring technique of KLa?
a) Dynamic gassing out method
b) Static method
c) Sulphite oxidation method
d) None of the mentioned
View Answer

Answer: d
Explanation: Dynamic gassing out method, Static method and Sulphite ore method are all measuring techniques of KLa.
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8. Which of the following is also called Oxygen balancing method?
a) Dynamic gassing out method
b) Static method
c) Sulphite oxidation method
d) None of the mentioned
View Answer

Answer: b
Explanation: Static method is also called Oxygen balancing method.

9. Sherwood number is _____
a) Product of schmidst and grashof number
b) Total mass transferred by mass transferred due to molecular diffusion
c) Product of schmidst and reynold number
d) None of the mentioned
View Answer

Answer: b
Explanation: Sherwood number is total mass transferred by mass transferred due to molecular diffusion.
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10. Rayleigh number is _____
a) Product of schmidst and grashof number
b) Total mass transferred by mass transferred due to molecular diffusion
c) Product of schmidst and reynold number
d) None of the mentioned
View Answer

Answer: a
Explanation: Rayleigh number is a product of schmidst and grashof number.

Sanfoundry Global Education & Learning Series – Food Engineering.

To practice all areas of Food Engineering for quizzes, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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