Unit Operations

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Statement 1: Apparent viscosity μ_a is related to shear stress (τ) and shear strain (γ) as μ_a= τ/γ.
True, False
True, True
False, False
False, True
Explanation:
Both the statements are true.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
Statement 1: Distillation is not used very widely in the food industry.
True, False
True, True
False, False
False, True
Explanation:
Distillation is not used very widely in the food industry. Steam distillation can be done when the volatile component is not miscible in water.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
Statement 1: Evaporation is considered a mass and heat transfer operation.
True, False
True, True
False, False
False, True
Explanation:
Evaporation is considered as a pure heat transfer operation. After evaporation, the solvent is left behind.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is NOT an important criteria for crystal formation?
Caking characteristics of the crystal
Moisture content
Shape
None of the mentioned
Explanation:
All the mentioned factors are important criteria for the formation of crystals.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Which of the following factors is a genuine criterion for the selection of a filter press?
Equipment life
Availability of floor area
Chemical reactivity
All of the mentioned
Explanation:
All of the mentioned factors are a genuine criterion for the selection of a filter press.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
A major reason as to why evaporators and their selection for different applications in the food industry is very important is because ______
Organoleptic characteristics of food is very important
Many food items are heat sensitive
Majority of them have high moisture content
All of the mentioned reasons
Explanation:
All the above mentioned reasons relevant to the question are true.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
Which of the following filtration equipment offers maximum pressure drop?
Plate and frame filter press
Pressure leaf filter press
Continuous Rotary Vacuum Filter Press
None of the mentioned
Explanation:
Pressure leaf filter press offers a maximum pressure drop.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Statement 1: Resistance is inversely proportional to the inter-facial area.
True, False
True, True
False, False
False, True
Explanation:
Resistance is inversely proportional to the inter-facial area. The inter-facial area of a body is the area of the dispersed phase in a unit volume of the vessel.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Multi-stage counter-current extraction is expensive as more extractors are needed to strip the solid off the solvent.
True
False
Explanation:
Multi-stage counter-current extraction is expensive as more extractors are needed to strip the solid off the solvent.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
After incipient fluidization, the pressure briefly _____
Increases
Decreases
Stays constant
Varies exponentially
Explanation:
After incipient fluidization, the pressure briefly decreases. This is because at incipient fluidization, the particles only become loose. They aren’t in contact with each other. They don’t start rising up. Hence, the pressure briefly decreases. Once they start moving up, the pressure increases.