Section 16

Question 1

Stoke’s law is valid, when the particle Reynolds number is
a. < 1
b. > 1
c. < 5
d. none of these

Answer 1

d. none of these

Question 2

Which of the following is not a dimension-less parameter?

a. Pressure-co-efficient
b. Froude number
c. Kinematic viscosity
d. Weber number

Answer 2

c. Kinematic viscosity

Question 3

In which of the following cases, it is possible for flow to occur from low pressure to high pressure ?

a. Flow of liquid upward in a vertical pipe.
b. Flow through a converging section.
c. Flow of air downward in a pipe.
d. Impossible in a constant cross-section conduit.

Answer 3

b. Flow through a converging section.

Question 4

The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades.

a. inlet tip of a blade curves in a direction opposite to that
b. outlet tip of a blade curves in a direction opposite to that
c. inlet tip of a blade is towards the direction
d. outlet tip of a blade is towards the direction

Answer 4

d. outlet tip of a blade is towards the direction

Question 5

For the same terminal conditions and fitting size, the least friction loss is incurred in a/an

a. T-joint
b. union
c. 45° elbow
d. 90°bend

Answer 5

b. union

Question 6

A floating/submerged body is always stable, if its centre of gravity

a. lies above its centre of buoyancy.
b. and centre of buoyancy coincide.
c. lies below its centre of buoyancy.
d. lies above its meta centre.

Answer 6

c. lies below its centre of buoyancy.

Question 7

Critical velocity in a pipe flow

a. increases as fluid viscosity increases.
b. increases as pipe diameter increases.
c. independent of fluid density.
d. none of these.

Answer 7

b. increases as pipe diameter increases.

Question 8

A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump

a. develops a lower head.
b. capacity is reduced.
c. requires more power.
d. all (a), (b) and (c).

Answer 8

d. all (a), (b) and (c).

Question 9

In an incompressible flow of fluid, the fluid

a. temperature remains constant.
b. compressibility is greater than zero.
c. density does not change with pressure & temperature.
d. is frictionless.

Answer 9

c. density does not change with pressure & temperature.

Question 10

The ratio of maximum to average velocity in case of streamline flow between parallel plates is

a. 1
b. 1.5
c. 2
d. 2.5

Answer 10

b. 1.5

Question 11

A weir is used to measure the large water discharge rate from a river or from an open channel. A weir is not of __________ shape.

a. circular
b. rectangular
c. triangular
d. trapezoidal

Answer 11

a. circular

Question 12

Pressure co-efficient is the ratio of pressure forces to __________ forces.

a. gravity
b. inertial
c. viscous
d. none of these

Answer 12

b. inertial

Question 13

Which of the following conditions must be satisfied for lift force to be developed ?

a. The body should be bluff body.
b. The body should be stream lined.
c. Circulation around the body is essentially required.
d. The main stream velocity must approach the velocity of sound in that fluid medium.

Answer 13

c. Circulation around the body is essentially required.

Question 14

The Reynolds number for an ideal fluid flow is
a. 4
b. 2100-4000
c. 4000
d. ∞

Answer 14

d. ∞