Fluid Mechanics MCQs

Question 1

Air vessel provided in a reciprocating pump is for

Accepted Answer

Making the friction in pipe uniform

Answer

Increasing the acceleration head

Answer

Decreasing the acceleration head

Answer

None of these

Question 2

Speed of sound in an ideal gas depends on its

Accepted Answer

Temperature

Answer

Pressure

Answer

Specific volume

Answer

None of these

Question 3

Which of the following options will facilitate the achievement of a very high head (say 30 metres) in case of a centrifugal pump?

Accepted Answer

Mounting of two or more impellers in series on a single shaft

Answer

Increasing the impeller speed and the volute area

Answer

Increasing the number of vanes in the impeller

Answer

Either of A, B or C

Question 4

In continuous fluidisation

Accepted Answer

Solids are completely entrained

Answer

The pressure drop is less than that for batch fluidisation

Answer

There is no entrainment of solids

Answer

Velocity of the fluid is very small

Question 5

Pick out the wrong statement.

Accepted Answer

In case of unsteady fluid flow, the velocity at any given point does not change with time

Answer

Surface tension of a liquid is because of the difference in magnitude of adhesive & cohesive forces

Answer

A hydrometer used for the determination of specific gravities of liquids works on the principle of buoyant forces

Answer

Turbulent fluid flow is characterised by the rapid fluctuation of instantaneous pressure & velocity at a point

Question 6

In parallel pipe problems, the

Accepted Answer

Head loss is the same through each pipe

Answer

Discharge is the same through all the pipes

Answer

Total head loss is equal to the sum of the head losses through each pipe

Answer

None of these

Question 7

In turbulent flow, the

Accepted Answer

Shear stresses are generally larger than in a similar laminar flow

Answer

Fluid particles move in an orderly manner

Answer

Momentum transfer is on molecular scale only

Answer

Shear stress is caused more effectively by cohesion than momentum transfer

Question 8

The boundary layer is that part of a moving fluid, in which the fluid velocity is

Accepted Answer

Affected by the presence of a solid boundary

Answer

Affected by the fluid flow pressure

Answer

Constant

Answer

All of the above

Question 9

A centrifugal pump designed for handling water (μ = 1 cp) will deliver __________ when pumping a thicker oil (μ = 30 cp).

Accepted Answer

Less head & capacity

Answer

More head

Answer

More capacity

Answer

Less head & more capacity