Food Engineering Questions and Answers – Unit Operations – Rheology of Foods

This set of Food Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Unit Operations – Rheology of Foods”.

1. Rheology of food in the food processing industry is how the food is affected when _____ is applied.
a) Pressure
b) Butter
c) None of the mentioned
d) All of the mentioned
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2. Statement 1: Starch is _____ as its viscosity decreases with an increase in shear stress.
Statement 2: Bingham plastics follow Newton’s law of viscosity at low shears.
a) Bingham, False
b) Dilatant, True
c) Pseudo plastic, False
d) Newtonian fluid, True
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3. Statement 1: Blood is a _____
Statement 2: Thixotropic fluids are fluids whose viscosity decreases when subjected to shear stress initially but eventually with time, the viscosity increases.
a) Newtonian fluid, False
b) Rheopectic, True
c) Pseudo plastic, False
d) Casson plastic, True
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4. Which of the flowing is true about two-parameter model?
a) It is also called as Ostwald-de Waele Model
b) The equation pertaining to it is τ=Kγⁿ
c) These equations pertain to Newtonian, dilatant and pseudo plastic fluids
d) All of the mentioned
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5. Statement 1: Apparent viscosity μ_a is related to shear stress (τ) and shear strain (γ) as μ_a= τ/γ.
Statement 2: The equation τ=Kγⁿ becomes μ_a= τ/γ = Kγ^(n-1) .
a) True, False
b) True, True
c) False, False
d) False, True
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6. Statement 1: In μ_a= τ/γ = Kγ^(n-1) , n = consistency index and K is the flow behaviour index.
Statement 2: n= 1 for Newtonian fluids, n<1 for dilatant fluids and n>1 for pseudo plastic fluids.
a) True, False
b) True, True
c) False, False
d) False, True
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7. Statement 1: Considering the equation, μ_a= τ/γ = Kγ^(n-1) , for pseudo plastic fluids, n<1 and they’re called Shear thinning liquids and dilatant fluids are called Shear thickening liquids as n>1.
Statement 2: Cooked starch solution is a Shear thinning liquid and dairy cream is a Shear thickening liquid.
a) True, False
b) True, True
c) False, False
d) False, True
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8. Which of the following is a name of an actual viscometer?
a) Capillary tube
b) Plate and Cone
c) Coaxial Cylinder
d) All of the mentioned
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9. Statement 1: Brookfield viscometer is an example of Coaxial Cylinder Viscometer.
Statement 2: Working principle of a Brookfield viscometer: Two coaxial cylinders. Liquid is filled in between them. The viscosity produces torque which is directly proportional to the shear stress.
a) True, False
b) True, True
c) False, False
d) False, True
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10. Statement 1: Brookfield viscometer is very robust, is supported by software and even shows values of K and n, but, sometimes particles suspended in the fluid cause problems.
Statement 2: Drawbacks of plate and cone viscometer: edge-effects, turbulence and temperature effects.
a) True, False
b) True, True
c) False, False
d) False, True
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Sanfoundry Global Education & Learning Series – Food Engineering.

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