4

# Head developed by a centrifugal pump is

Proportional to diameter of impeller

Proportional to speed of impeller

Proportional to diameter and speed of impeller

None of the above

C. Proportional to diameter and speed of impeller

4

# According to fan laws, for fans having constant wheel diameter, the air or gas capacity varies

Directly as fan speed

Square of fan speed

Cube of fan speed

Square root of fan speed

4

(W/p) × (A/a)

(p/W) × (a/A)

(W/p) × (a/A)

(p/W) × (A/a)

4

Double

Three times

Four times

Five times

4

One-fourth

One-half

Three-fourth

Double

4

# If the net positive suction head (NPSH) requirement for the pump is not satisfied, then

No flow will take place

Cavitation will be formed

Efficiency will be low

Excessive power will be consumed

4

(D/2d) + 5

(D/2d) + 10

(D/2d) + 15

(D/2d) + 20

4

Decreases

Increases

Remain same

None of these

4

N√P / H3/2

N√P / H²

N√P / H5/4

N√P / H3

4

# The cavitation in reaction turbines is avoided, to a great extent by

Installing the turbine below the tail race level

Using stainless steel runner of the turbine

Providing highly polished blades to the runner

All of the above

4

P/ √H

P/ H

P/ H3/2

P/ H²

4

# The efficiency of jet propulsion for a ship with inlet orifices at right angles to the direction of motion of ship is given by

[2(Vr - v) v]/ Vr²

2(Vr + v) v]/ Vr²

[(Vr - v) v]/ Vr

[(Vr + v) v]/ Vr

4

# Which of the following pump is successfully used for lifting water to the boilers?

Centrifugal pump

Reciprocating pump

Jet pump

Airlift pump

4

# The ratio of quantity of liquid discharged per second from the pump to the quantity of liquid passing per second through the impeller is known as

Manometric efficiency

Mechanical efficiency

Overall efficiency

Volumetric efficiency

4

2 to 4

4 to 8

8 to 16

16 to 24

4

# The working of which of the following hydraulic units is based on Pascal's law?

Air lift pump

Jet pump

Hydraulic coupling

Hydraulic press

4

# Impulse turbine is generally fitted

At the level of tail race

Little above the tail race

Slightly below the tail race

About 2.5 m above the tail race to avoid cavitations.

4

0.25 m3/s

0.5 m3/s

1.5 m3/s

2.5 m3/s

4

(1 + cos φ)/2

(1 - cos φ)/2

(1 + sin φ)/2

(1 - sin φ)/2

4

# Which of the following pump is preferred for flood control and irrigation applications?

Centrifugal pump

Axial flow pump

Mixed flow pump

Reciprocating pump

4

0.50 to 0.65

0.65 to 0.75

0.75 to 0.85

0.85 to 0.90

4

Axial

Centrifugal

Vortex

4

Turgo turbine

Pelton wheel

Kaplan turbine

4

0.15 to 0.3

0.4 to 0.5

0.6 to 0.9

1 to 1.5

4

# If the ratio's of the corresponding forces acting at corresponding points are equal, then the model and the prototype are said to have.

Geometric similarity

Kinematic similarity

Dynamic similarity

None of these

4

# The cavitation in a hydraulic machine

Causes noise and vibration of various parts

Reduces the discharge of a turbine

Causes sudden drop in power output and efficiency

All of the above

4

# Francis, Kaplan and propeller turbines fall under the category of

Impulse turbines

Reaction turbines

Axial flow turbines

Mixed flow turbines

4

Greater than 15°

Greater than 8°

Greater than 5°

Less than 8°

4

Hydraulic

Mechanical

Overall

None of these

4

# According to fan laws, for the fans having constant wheel diameters, the power demand varies

Directly as fan speed

Square of fan speed

Cube of fan speed

Square root of fan speed