Fluid Mechanics MCQs

Question 1

Which of the following equations as suggested by Colebrook and White gives the increase in roughness of a new surface (ε 0 ) with age/time (t) (where, ε = roughness of the surface after time 't'. α = a co-efficient to be experimentally determined)?

Accepted Answer

ε = ε 0 + α.t

Answer

ε = ε 0 + α.t 2

Answer

ε = ε 0 + α.t 3

Answer

ε = ε 0 + α.t 4

Question 2

In a dry packed bed, the pressure drop will be changed by increasing the flow rate as

Accepted Answer

V 1.8

Answer

V -0.8

Answer

V

Answer

V -1

Question 3

An isentropic process is the one, in which

Accepted Answer

pv r = constant, and process is reversible

Answer

pv = constant

Answer

pv r = constant

Answer

None of these

Question 4

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, then the new head will be __________ metres.

Accepted Answer

2

Answer

4

Answer

8

Answer

5.5

Question 5

Discharge from a 24 inch pipe of water at 10 ft/sec will be __________ ft 3 /sec.

Accepted Answer

125.6

Answer

7.65

Answer

32.36

Answer

48.22

Question 6

The dimension of dynamic viscosity is

Accepted Answer

ML -1 T -1

Answer

L 2 T -1

Answer

LT -2

Answer

ML -1 T -2

Question 7

Pick out the correct statement pertaining to transition/ entrance length in fluid flow.

Accepted Answer

All of the above

Answer

The length of entrance region of pipe, in which full development of fluid flow takes place such that velocity profile does not change downstream, is called the transition length

Answer

Transition length for laminar flow of Newtonion fluids in a pipe of diameter 'd' is equal to 0.05. D.N Re

Answer

Transition length for turbulent flow of Newtonion fluids in a smooth pipe of diameter 'd' is equal to 50 D

Question 8

The terminal velocity of a particle moving through a fluid varies as d p n . What is the value of 'n' for Newton's law regime?

Accepted Answer

0.5

Answer

1

Answer

1.5

Answer

3

Question 9

A free jet of water of cross-sectional area 0.01 m 2 and a velocity of 20 m/s strikes a plate and then flows in a plane parallel to the plate as shown in the figure below. The horizontal component of the force on the support is

Accepted Answer

4000 N

Answer

200 N

Answer

400 N

Answer

2000 N