# Fluid Mechanics Questions and Answers – Methods of Determination of Coefficient of Viscosity

This set of Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Methods of Determination of Coefficient of Viscosity”.

1. What is the unit of coefficient of viscosity?
a) kgsm-2
b) kgms-2
c) Nms-2
d) Nsm-2

Explanation: Coefficient of viscosity is defined as the degree to which the fluid resists flow under an applied force. It is expressed as ratio of shearing stress to the velocity gradient. The unit is Nsm-2.

2. What happens to the coefficient of viscosity if the temperature increases?
a) Increases
b) Decreases
c) Remains the same
d) Independent of temperature

Explanation: With the increase in temperature, the coefficient of viscosity of fluid decreases. This happens due to the weakening of bonds between the molecules. Because of its dash pot coefficient, the flow attains peak deformation.

3. What is the magnitude of the coefficient of viscosity?
a) Frictional force/Area
b) Frictional force/ (Area* velocity gradient)
c) Frictional force*Area

Explanation: Coefficient of viscosity is defined as the degree to which the fluid resists flow under an applied force. It is expressed as a ratio of shearing stress to the velocity gradient. It has a unit of Nsm-2.

4. Which among the following methods are not standard laboratory viscometers?
a) Saybolt Viscometer
b) Redwood Viscometer
c) Ostwald Viscometer
d) Vibrational viscometer

Explanation: Vibrational viscometer is a viscometer that serves the same purpose as the other viscometers. But, it is not used for laboratory purposes. It measures the damping oscillations using a resonator immersed in a fluid.

5. What is the formula for coefficient of static friction?
a) R/F
b) F*R
c) F/R
d) F+R

Explanation: Coefficient of static friction is defined as the ratio of limiting frictional force to the normal reaction force. Limiting frictional force is denoted by ‘F’ and normal frictional force is denoted by ‘R’. Therefore, option ‘c’ is correct.

6. What is the dimension for coefficient of friction?
a) [M][L][T]
b) [M][L][T]2
c) It has no dimensions
d) [M][L]-1[T]-1

Explanation: Coefficient of static friction is defined as the ratio of limiting frictional force to the normal reaction force. Dividing the dimensions of the limiting frictional force and normal frictional force, the units cancel out each other due to which it has no dimensions.

7. Where is friction a drawback?
b) On pipes
c) Staircase
d) Playground

Explanation: Friction in pipes lead to major and minor loses. It is an economic significance. It provides a lot of confusions on whether the pipe or duct is entirely closed. It leads to a high amount of power loss in drawing fluid through the pipes.

8. Measuring the coefficient of static friction takes place by_________
a) Tilting two objects
b) Keeping it stationery
c) Reciprocating
d) Rotating

Explanation: The easiest way to measure the coefficient of static friction is by placing the two objects together and tilting them until one object slides over the other. Coefficient is related to the angle at which one object starts to slide over the other.

9. Coefficient of kinetic friction can be found out by inclined plane method and horizontal plane method.
a) True
b) False

Explanation: Coefficient of kinetic friction can be found out by inclined plane method and horizontal plane method. In case of inclined plane, the block slides down on an incline with a constant velocity. In the horizontal plane method, the block does not slide and produces nil friction.

10. Which among the following is used to determine the angle of repose?
a) Horizontal plane method
b) Tilting box method
c) Fixed funnel method
d) Revolving cylinder method

Explanation: Angle of repose is defined as the steepest angle of descent or dip. It is with relation to the horizontal plane to which a material can be piled. Example: When we pile up stones one over the other, the stones tend to slide along the heap at a certain point. The angle at that point is the angle of repose.

11. What is the maximum value for the angle of repose?
a) 30
b) 60
c) 90
d) 180

Explanation: Angle of repose is defined as the steepest angle of descent or dip. It is with relation to the horizontal plane to which a material can be piled. The maximum value for the angle of repose is 90 degrees. It is exactly perpendicular to the horizontal surface.

12. What is the minimum value for angle of repose?
a) 0
b) 60
c) 90
d) 180

Explanation: Angle of repose is defined as the steepest angle of descent or dip. It is with relation to the horizontal plane to which a material can be piled. The minimum value for angle of repose is zero degrees. It lies on the horizontal surface. Therefore, there is no sliding.

Sanfoundry Global Education & Learning Series – Fluid Mechanics.

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