Engineering Questions with Answers - Multiple Choice Questions
Food Engineering MCQ’s – Unit Operations – Diffusion and Mass Transfer-2
1 - Question
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
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 - Question
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
Explanation: The existence of a thick constant film between two phases is a proposal by the Film theory.
3 - Question
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
Explanation: Film theory states that mass transfer coefficient is directly proportional to diffusivity coefficient which was later proved wrong.
4 - Question
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
Explanation: In Penetration theory, mass transfer coefficient is proportional to D1/2 Penetration theory.
5 - Question
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
Explanation: Surface renewal theory proposes that the film is continuously getting renewed and replaced by the bulk liquid.
6 - Question
Statement 1: KLa is measured together and not separately.
a) True
b) False
View Answer
Explanation: KLa is measured together and not separately.
7 - Question
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
Explanation: Dynamic gassing out method, Static method and Sulphite ore method are all measuring techniques of KLa.
8 - Question
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
Explanation: Static method is also called Oxygen balancing method.
9 - Question
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
Explanation: Sherwood number is total mass transferred by mass transferred due to molecular diffusion.
10 - Question
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
Explanation: Rayleigh number is a product of schmidst and grashof number.