Fluid Mechanics MCQs

Question 1

The simple pitot tube does not measure the

Accepted Answer

All of the above

Answer

Static pressure

Answer

Dynamic pressure

Answer

Velocity at the stagnation point

Question 2

Pick out the wrong statement.

Accepted Answer

Newton's law of viscosity is not applicable to the turbulent flow of fluid with linear velocity distribution

Answer

A fluid mass is free from shearing forces, when it is made to rotate with a uniform velocity

Answer

Laminar flow of viscous liquids is involved in the lubrication of various types of bearings

Answer

Rise of water in capillary tubes reduces with the increasing diameter of capillary tubes

Question 3

The head loss in turbulent flow in pipe is proportional to (where, V = velocity of fluid through the pipe)

Accepted Answer

V2

Answer

$$\frac{1}{{{{	ext{V}}^2}}}$$

Answer

$$\frac{1}{{	ext{V}}}$$

Answer

V

Question 4

For pipe flows, head is proportional to __________ at constant capacity (where, D = pipe diameter).

Accepted Answer

$$\frac{1}{{{{	ext{D}}^5}}}$$

Answer

$$\frac{1}{{	ext{D}}}$$

Answer

$$\frac{1}{{{{	ext{D}}^2}}}$$

Answer

D2

Question 5

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpmHead = 8 metresFlow = 1000 litres/minutes.If its speed is halved, the new discharge will be __________ litres/minute.

Accepted Answer

500

Answer

200

Answer

1000

Answer

750

Question 6

Pick out the correct statement.

Accepted Answer

Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow

Answer

Fanning friction factor is inversely proportional to Reynolds number always

Answer

The property of a randomly packed bed (with raschig rings) is given by the ratio of the total volume to the volume of voids in the bed

Answer

Mach number in an incompressible fluid is always unity

Question 7

Potential flow is characterised by the

Accepted Answer

Irrotational and frictionless flow

Answer

Irrotational and frictional flow

Answer

One in which dissipation of mechanical energy into heat occurs

Answer

Formation of eddies within the stream

Question 8

Multistage centrifugal pumps are generally used for

Accepted Answer

High head

Answer

Low head but high discharge

Answer

Highly viscous liquid

Answer

Slurries of high solid concentration

Question 9

Remote control valve is a __________ valve.

Accepted Answer

Butterfly

Answer

Gate

Answer

Needle

Answer

Globe