This set of Dairy Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Definition and Basic”.
1. Why is it necessary to study flow behavior in dairy?
a) To design food processing plant
b) To prevent spoilage
c) To design food processing plant and prevent spoilage
d) For nutrition
Explanation: Study of flow behavior is important for the designing of food processing plant. In the dairy industry; in particular, there are cream and cultured milk products whose characteristics can be partially or completely spoiled if their flow behavior is not understood.
2. The science of deformation and flow of matter is called _____
Explanation: Rheology is defined as the science of deformation and flow of matter. Bending is one of the flow behaviors.
3. Consistency can be described as :
d) Viscosity and elasticity
Explanation: Rheologically the consistency is described by two components, the viscosity (“thickness”, lack of slipperiness) and the elasticity (“stickiness”, structure). Breakability is the quality of being easily damaged or destroyed.
4. Rheology stands for viscosity measurements, characterisation of flow behavior and determination of material structure. State true or false.
Explanation: Rheology involves viscosity measurements; it involves characterization of flow behavior and determination of material structure. Basic knowledge of these subjects is essential in process design and product quality evaluation.
5. The time required to reduce a stress in the material by flow is called __________
a) Peak time
b) Relaxation time
c) Stress time
d) No time
Explanation: One way of characterizing a material is by its relaxation time, i.e. the time required to reduce a stress in the material by flow. It is important to study flow behavior of the milk.
6. Milk is a ______ fluid.
Explanation: Gases and liquids are normally described as viscous fluids. An ideal viscous fluid is unable to store any deformation energy.
7. Which fluids are having a constant viscosity dependent on temperature but independent of the applied shear rate?
a) Non- Newtonian
Explanation: Newtonian fluids are those having a constant viscosity dependent on temperature but independent of the applied shear rate. Dry and wet are irrelevant.
8. A Newtonian fluid is defined as the fluid which?
a) Obeys hook’s law
b) Is compressible
c) Obey Newton’s law of viscosity
d) Is incompressible
Explanation: Newtonian fluid is defined as the fluid which obeys Newton’s law of viscosity for a Newtonian fluid. The viscosity curve, which is a plot of viscosity versus shear rate, will show a straight line at a constant value equal to h.
9. Property of fluid that describes its internal resistance is known as:
d) Internal energy
Explanation: Property of fluid that describes its internal resistance is called viscosity. Friction is the force resisting the relative motion of fluid layers.
10. Stress strain relationship for Newtonian fluid is :
d) Inverse type
Explanation: Newtonian fluid has a linear stress strain relationship. The increase in stress directly corresponds to increase in strain.
11. For non-Newtonian fluids, apparent viscosity is a function of :
a) shear rate
b) flow rate
c) viscous rate
d) specific rate
Explanation: Non Newtonian fluid apart from being shear rate dependent .The viscosity of non-Newtonian fluids may also be time dependent.
b) Non Newtonian
Explanation: The above diagram represents the relationship between Shear stress and velocity gradient of Non- Newtonian fluid. It is non-linear.
13. Which of the following are now Newtonian material which are time independent?
Explanation: Non-Newtonian materials that are time independent are defined as shear thinning. They can also be shear thickening or plastic.
14. Which of the following are now Newtonian materials which are time dependent?
a) Shear thickening
c) Shear thinning
Explanation: Non-Newtonian materials that are time dependent are defined as thixotropic. They can also be rheopectic or anti-thixotropic.
15. Which among the following is not the example of thixotropic fluid?
b) Ice cream
Explanation: Typical examples of thixotropic fluids are yoghurt. Mayonnaise, margarine, ice cream and brush paint also come in the same category.
Sanfoundry Global Education & Learning Series – Dairy Engineering.
To practice all areas of Dairy Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.