INDIABIX-FLUID MECHANICS

Question 1

The fluid property, due to which, mercury does not wet the glass is

surface tension
viscosity
cohesion
adhesion

Answer 1

surface tension

Question 2

When the momentum of one fluid is used for moving another fluid, such a device is called a/an

jet pump
blower
acid egg
none of these

Answer 2

jet pump

Question 3

The head loss in turbulent flow in a pipe varies

as velocity
as (velocity)2
inversely as the square of diameter
inversely as the velocity

Answer 3

as (velocity)2

Question 4

Most commonly used joint in the underground pipe lines is the

sleevejoint
coupling
flange
expansion joint

Answer 4

sleevejoint

Question 5

Schedule number of a pipe, which is a measure of its wall thickness, is given by

1000 P’/S
100 P’/S
1000 S/P’
10000 P’/S

Answer 5

1000 P’/S

Question 6

The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the

A) discharge.
B) suction.
C) suction minus vapor pressure of the liquid at suction temperature.
D) discharge minus vapor pressure of the liquid at the discharge temperature.

Answer 6

C) suction minus vapor pressure of the liquid at suction temperature.

Question 7

With increasing flow rate, the hydraulic efficiency of a centrifugal pump

monotonically decreases.
decreases and then increases.
remains constant.
increases and then decreases.

Answer 7

monotonically decreases.

Question 8

The velocity profile for turbulent flow through a closed conduit is

logarithmic
parabolic
hyperbolic
linear

Answer 8

logarithmic

Question 9

Water hammer in a pipeline results from the

A) bursting of pipelines due to closure by a valve.
B) rapid pressure change due to a rapid change in the rate of flow.
C) pressure increase due to closure of a valve resulting in decrease in rate of flow.
D) none of these

Answer 9

B) rapid pressure change due to a rapid change in the rate of flow.

Question 10

Molten soap mass is transported by a __________ pump.

diaphragm
reciprocating
gear
centrifugal

Answer 10

centrifugal

Question 11

Which of the following denotes the effect of compressibility in fluid flow ?

Weber number
Mach number
Euler number
Reynolds number

Answer 11

Mach number

Question 12

Foot valves provided in pumps are __________ valves.

relief
three/four way
pressure reducing
directional control

Answer 12

directional control

Question 13

At high Reynolds number,

A) inertial forces control and viscous forces are unimportant.
B) viscous forces predominate.
C) inertial forces are unimportant and viscous forces control.
D) none of these.

Answer 13

A) inertial forces control and viscous forces are unimportant.

Question 14

Power loss in an orificemeter is __________ that in a venturimeter.

less than
same as
more than
data insufficient, cannot be predicted

Answer 14

more than

Question 15

The fluid in which the shearing stress within it is proportional to the velocity gradient across the sheared section, is called a __________ fluid.

Bingham
Newtonian
perfect
none of these

Answer 15

Newtonian

Question 16

In fluid flow, cavitation is caused, if the

A) fluid velocity decreases to zero.
B) total energy decreases.
C) both (a) and (b).
D) flow pressure approaches its vapor pressure at the prevailing temperature.

Answer 16

D) flow pressure approaches its vapor pressure at the prevailing temperature.

Question 17

The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is

0.5
1
1.5
2

Answer 17

2

Question 18

The maximum delivery pressure of compressors can be up to __________ atmospheres.

10
100
250
1000

Answer 18

1000

Question 19

All pipes of a particular nominal size have the same

inside diameter
outside diameter
thickness
none of these

Answer 19

outside diameter

Question 20

For the transfer of solution of thick slurry, the pump used is a __________ pump.

reciprocating
gear
diaphragm
centrifugal

Answer 20

diaphragm

Question 21

Which of the following is not concerned with the fluid-particle interaction ?

Drag co-efficient
Froude number
Galileo number
Weber number

Answer 21

Weber number

Question 22

__________ pumps are axial flow pumps.

Turbine
Propeller
Diffuser
none of these

Answer 22

Propeller

Question 23

For a particle settling in water at its terminal settling velocity, which of the following is true ?

Buoyancy = weight + drag
Weight = buoyancy + drag
Drag = buoyancy + weight
Drag = weight

Answer 23

Weight = buoyancy + drag

Question 24

Shear stress in a fluid flowing in a round pipe

varies parabolically across the cross-section.
remains constant over the cross-section.
is zero at the centre and varies linearly with the radius.
is zero at the wall and increases linearly to the centre.

Answer 24

is zero at the centre and varies linearly with the radius.

Question 25

The resistance wire used in a hot wire anemometer for conducting electrical current is made of

copper
tungsten
chromium
aluminum

Answer 25

tungsten