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

A. [2(Vr - v) v]/ Vr²

4

ηh = ηo × ηm

ηm = ηm × ηh

ηo = ηh × ηm

None of these

4

Same

0.75 B.H.P.

B.H.P./0.75

1.5 B.H.P.

4

175.4 r.p.m.

215.5 r.p.m.

241.5 r.p.m.

275.4 r.p.m

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

10-15°

20-25°

30-40°

50-60°

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

4

# If a pump is handling water and is discharging a certain flow Q at a constant total dynamic head requiring a definite B.H.P., the same pump when handling a liquid of specific gravity 0.75 and viscosity nearly same as of water would discharge

Same quantity of liquid

0.75 Q

Q/0.75

1.5 Q

4

# Which of the following is not a reaction turbine?

Fourneyron turbine

Journal turbine

Thomson's turbine

Pelton wheel

4

# Delivery head of a centrifugal pump is

Directly proportional to N

Inversely proportional to N

Directly proportional to N²

Inversely proportional to N²

4

Decreases

Increases

Remain same

None of these

4

# Which of the following hydraulic unit is used for transmitting increased or decreased torque to the driven shaft?

Hydraulic ram

Hydraulic intensifier

Hydraulic torque converter

Hydraulic accumulator

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

# 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

# In order to avoid cavitation in centrifugal pumps

The suction pressure should be high

The delivery pressure should be high

The suction pressure should be low

The delivery pressure should be low

4

# Which place in hydraulic turbine is most susceptible for cavitations?

Inlet of draft rube

Penstock

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

Centrifugal

Axial flow

Mixed flow

Reciprocating

4

# In an inward flow reaction turbine

The water flows parallel to the axis of the wheel

The water enters at the centre of the wheel and then flows towards the outer periphery of the wheel

The water enters the wheel at the outer periphery and then flows towards the centre of the wheel

The flow of water is partly radial and partly axial

4

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

Centrifugal pump

Reciprocating pump

Jet pump

Air lift pump

4

24.8 r.p.m.

48.2 r.p.m

82.4 r.p.m.

248 r.p.m

4

Equal to

1.2 times

1.8 times

Double

4

(D/2d) + 5

(D/2d) + 10

(D/2d) + 15

(D/2d) + 20

4

# Motion of a liquid in a volute casing of a centrifugal pump is an example of

Rotational flow

Forced spiral vortex flow

Spiral vortex flow

4

Two jets

Two runners

Four jets

Four runners

4

# Discharge of a centrifugal pump is

Directly proportional to diameter of its impeller

Inversely proportional to diameter of its impeller

Directly proportional to (diameter)² of its impeller

Inversely proportional to (diameter)² of its impeller

4

# Pressure intensifier increases the pressure in proportion to

Ratio of diameters

Square of ratio of diameters

Inverse ratio of diameters

Square of inverse ratio of diameters

4

# In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by

Designing new impeller

Trimming the impeller size to the required size by machining

Not possible

Some other alterations in the impeller

4

Normal speed

Unit speed

Specific speed

None of these

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