Fluid Mechanics MCQs

Question 1

For the laminar flow of a fluid in a circular pipe of radius R, the Hagen-Poisseule equation predicts the volumetric flow rate to be proportional to

Accepted Answer

R4

Answer

R

Answer

R2

Answer

R0.5

Question 2

When a fluid flows over a solid surface, the

Accepted Answer

Velocity gradient is zero at the solid surface

Answer

Velocity is uniform at any cross-section

Answer

Resistance between the surface & the fluid is lesser as compared to that between the fluid layers themselves

Answer

Velocity is not zero at the solid surface

Question 3

Which of the following can be used for the direct measurement of volumetric flow rate of slurry?

Accepted Answer

Rotameter

Answer

Venturimeter

Answer

Orificemeter

Answer

Pitot tube

Question 4

In case of a pipe of constant cross-sectional area, the maximum fluid velocity obtainable is

Accepted Answer

The velocity of sound

Answer

Dependent on its cross-sectional area

Answer

Dependent on fluid viscosity

Answer

Dependent on fluid density

Question 5

Minimum porosity for fluidisation is

Accepted Answer

The porosity of the bed when true fluidisation begins

Answer

That corresponding to static bed

Answer

That corresponding to completely fluidised bed

Answer

Less than that of the static bed

Question 6

For turbulent flow of newtonion fluid in a circular cross-section pipe, the ratio of maximum to average fluid velocity is

Accepted Answer

1

Answer

0.5

Answer

0.66

Answer

< 0.5

Question 7

Efficiency of power transmission (η) through a circular pipe is given by $$\frac{{{{	ext{h}}_{	ext{t}}} - {{	ext{h}}_{	ext{f}}}}}{{{{	ext{h}}_{	ext{t}}}}},$$ which has a maximum value of __________ percent.

Accepted Answer

66.6

Answer

33.3

Answer

50

Answer

88.8

Question 8

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 power consumed now will be __________ hp.

Accepted Answer

0.5

Answer

2

Answer

4

Answer

1

Question 9

Pick out the wrong statement pertaining to fluid flow.

Accepted Answer

The ratio of average velocity to the maximum velocity for turbulent flow of Newtonion fluid in circular pipes is 0.5

Answer

The Newtonion fluid velocity in a circular pipe flow is maximum at the centre of the pipe

Answer

Navier-Stokes equation is applicable to the analysis of viscous flows

Answer

Hagen-Poiseuille equation is applicable to the laminar flow of Newtonion fluids