Fluid Mechanics MCQs

Question 1

Discharge in laminar flow through a pipe varies

Accepted Answer

As the square of the radius

Answer

Inversely as the pressure drop

Answer

Inversely as the viscosity

Answer

As the square of the diameter

Question 2

In the complete turbulence zone (in rough pipes), the

Accepted Answer

Friction factor is independent of the relative roughness

Answer

Rough and smooth pipes have the same friction factor

Answer

Laminar film covers the roughness projections

Answer

Friction factor depends upon NRe only

Question 3

What is the speed of sound (m/sec) in ordinary water?

Accepted Answer

1500

Answer

330

Answer

1000

Answer

3000

Question 4

The effect of solid boundary on the fluid flow is confined to the boundary layer, except for fluids

Accepted Answer

Both A and B

Answer

Having high viscosities

Answer

Moving at low velocities

Answer

Neither A nor B

Question 5

The losses in open channel flow generally vary as the

Accepted Answer

First power of the roughness

Answer

Inverse of the roughness

Answer

Square of the velocity

Answer

Inverse square of hydraulic radius

Question 6

What is the unit of kinematic viscosity in SI unit?

Accepted Answer

m2/sec

Answer

N/m2.sec

Answer

Kg.sec/m

Answer

None of these

Question 7

If Blausius or Darcey friction factor is 'f1' then the Fanning friction factor is equal to

Accepted Answer

$$\frac{{{{	ext{f}}_1}}}{4}$$

Answer

4f2

Answer

2f1

Answer

$$\frac{{{{	ext{f}}_1}}}{2}$$

Question 8

Nature of fluid flow during the opening of a valve in a pipeline is

Accepted Answer

Unsteady

Answer

Laminar

Answer

Steady

Answer

Uniform

Question 9

The equivalent diameter for pressure drop calculation for a fluid flowing through a rectangular cross-section channels having sides 'x' & 'y' is given by

Accepted Answer

$$\frac{{2{	ext{xy}}}}{{{	ext{x}} + {	ext{y}}}}$$

Answer

$$\frac{{{	ext{xy}}}}{{{	ext{x}} + {	ext{y}}}}$$

Answer

$$\frac{{{	ext{x}} + {	ext{y}}}}{{2{	ext{xy}}}}$$

Answer

$$\frac{{{	ext{x}} + {	ext{y}}}}{{{	ext{xy}}}}$$