Fluid Mechanics MCQs

Question 1

Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the __________ decreases.

Accepted Answer

All of the above

Answer

NPSH required

Answer

BHP required by the pump

Answer

Head of the liquid pumped

Question 2

In laminar flow through a round tube, the discharge varies

Accepted Answer

Inversely as the viscosity

Answer

Linearly as the viscosity

Answer

Inversely as the pressure drop

Answer

As the square of the radius

Question 3

What is the ratio of displacement thickness to nominal thickness for a linear distribution of velocity in the boundary layer on a flat plate?

Accepted Answer

0.5

Answer

1

Answer

1.5

Answer

2

Question 4

The hydrodynamic and thermal boundary layers will merge, when

Accepted Answer

Prandtl number is one

Answer

Schmidt number tends to infinity

Answer

Nusselt number tends to infinity

Answer

Archimedes number is greater than 10000

Question 5

Unit of mass velocity is

Accepted Answer

Kg/m2.hr

Answer

Kg/hr

Answer

Kg/m2

Answer

Kg/m3.hr

Question 6

Scale up of agitator design requires

Accepted Answer

All of the above

Answer

Geometrical similarity only

Answer

Dynamic similarity only

Answer

Both geometrical and dynamic similarity

Question 7

A centrifugal pump is called a turbine pump, if it is having a

Accepted Answer

Vaned diffusion casing

Answer

Turbine type impeller

Answer

Rotating vaned volute

Answer

None of these

Question 8

The head loss in turbulent flow in a pipe varies

Accepted Answer

As (velocity)2

Answer

As velocity

Answer

Inversely as the square of diameter

Answer

Inversely as the velocity

Question 9

The head loss in turbulent flow in a pipe varies

Accepted Answer

Approximately as the square of the velocity

Answer

Directly as the velocity

Answer

Inversely as the square of the velocity

Answer

Inversely as the square of the diameter