Fluid Mechanics MCQs

Question 1

Medium viscosity lubricating oil can be most ideally pumped by a __________ pump.

Accepted Answer

Vane

Answer

Piston

Answer

Centrifugal

Answer

Plunger

Question 2

Reynolds number for water flow through a tube of I.D. 5 cm is 1500. If a liquid of 5 centipoise viscosity and 0.8 specific gravity flows in the same pipe at the same velocity, then the pressure drop will

Accepted Answer

Increase

Answer

Decrease

Answer

Remain same

Answer

Data insufficient to predict pressure drop

Question 3

If two capillary tubes of dia 0.5 mm and 1 mm are dipped in a pot containing mercury, then the rise of mercury is

Accepted Answer

Greater in 0.5 mm dia tube

Answer

Same in both the tubes

Answer

Greater in 1 mm dia tube

Answer

Zero in both the tubes

Question 4

Boundary layer separation occurs when the

Accepted Answer

Cross-section of the channel is reduced

Answer

Pressure reaches a minimum

Answer

Valve is closed in a pipeline

Answer

Velocity of sound is reached

Question 5

A stream line is

Accepted Answer

Fixed in space in steady flow

Answer

Always the path of particle

Answer

Drawn normal to the velocity vector at every point

Answer

A line connecting the mid points of flow cross-section

Question 6

The unit of dynamic viscosity in SI unit is

Accepted Answer

kg/m . sec

Answer

N/m2

Answer

m2 /sec

Answer

m/N. sec

Question 7

The value of critical Reynolds number for pipe flow is

Accepted Answer

1300

Answer

10000

Answer

1,00,000

Answer

None of these

Question 8

For an unstable equilibrium of a floating body (where, M = metacentre.)

Accepted Answer

M is below G

Answer

M is above G

Answer

M &a G coincidemp

Answer

None of these

Question 9

What is the value of Fanning friction factor f ' for smooth pipe at N Re = 10 6 approximately?

Accepted Answer

0.003

Answer

0.01

Answer

0.1

Answer

0.3