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4

The maximum number of jets generally employed in impulse turbine without jet interference is

A. 4

B. 6

C. 8

D. 12

Correct Answer :

B. 6


Related Questions

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4

One horsepower is equal to

A. 102 watts

B. 75 watts

C. 550 watts

D. 735 watts

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4

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

A. Directly as fan speed

B. Square of fan speed

C. Cube of fan speed

D. Square root of fan speed

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4

The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as

A. Normal speed

B. Unit speed

C. Specific speed

D. None of these

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4

In an outward flow reaction turbine

A. The water flows parallel to the axis of the wheel

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

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

D. The flow of water is partly radial and partly axial

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4

The hydraulic efficiency of an impulse turbine is maximum when velocity of wheel is _______ of the jet velocity,

A. One-fourth

B. One-half

C. Three-fourth

D. Double

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4

The centrifugal pump preferred for a specific speed between 80 to 160 r.p.m. is

A. Slow speed with radial flow at outlet

B. Medium speed with radial flow at outlet

C. High speed with radial flow at outlet

D. High speed with mixed flow at outlet

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4

In reaction turbine, draft tube is used

A. To transport water downstream without eddies

B. To convert the kinetic energy to flow energy by a gradual expansion of the flow cross-section

C. For safety of turbine

D. To increase flow rate

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4

In axial flow fans and turbines, fluid enters and leaves as follows

A. Radially, axially

B. Axially, radially

C. Axially, axially

D. Radially, radially

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4

The specific speed of a centrifugal pump, delivering 750 litres of water per second against a head of 15 metres at 725 r.p.m., is

A. 24.8 r.p.m.

B. 48.2 r.p.m

C. 82.4 r.p.m.

D. 248 r.p.m

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4

Which of the following pump is successfully used for lifting water from deep wells?

A. Centrifugal pump

B. Reciprocating pump

C. Jet pump

D. Air lift pump

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4

The width of the bucket for a Pelton wheel is generally ________ the diameter of jet.

A. Double

B. Three times

C. Four times

D. Five times

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4

Any change in load is adjusted by adjusting following parameter on turbine

A. Net head

B. Absolute velocity

C. Blade velocity

D. Flow

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4

The cavitation in a hydraulic machine is mainly due to

A. Low velocity

B. High velocity

C. Low pressure

D. High pressure

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4

The specific speed (Ns) of a centrifugal pump is given by

A. (N√Q)/H2/3

B. (N√Q)/H3/4

C. (N√Q)/H

D. (N√Q)/H5/4

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4

Guide angle as per the aerofoil theory of Kaplan turbine blade design is defined as the angle between

A. Lift and resultant force

B. Drag and resultant force

C. Lift and tangential force

D. Lift and drag

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4

Multistage centrifugal pumps are used to

A. Give high discharge

B. Produce high heads

C. Pump viscous fluids

D. All of these

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4

Saving of work done and power by fitting an air vessel to single acting reciprocating pump is of the order of

A. 39.2 %

B. 49.2 %

C. 68.8 %

D. 84.8 %

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4

A double overhung Pelton wheel has

A. Two jets

B. Two runners

C. Four jets

D. Four runners

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4

Maximum impulse will be developed in hydraulic ram when

A. Waste valve closes suddenly

B. Supply pipe is long

C. Supply pipe is short

D. Ram chamber is large

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4

A Francis turbine is used when the available head of water is

A. 0 to 25 m

B. 25 m to 250 m

C. Above 250 m

D. None of these

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4

A Pelton wheel develops 1750 kW under a head of 100 metres while running at 200 r.p.m. and discharging 2500 litres of water per second. The unit speed of the wheel is

A. 10 r.p.m.

B. 20 r.p.m.

C. 40 r.p.m.

D. 80 r.p.m.

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4

A hydraulic press is a device used

A. To store pressure energy which may be supplied to a machine later on

B. To increase the intensity of pressure of water by means of energy available from a large quantity of water at a low pressure

C. To lift larger load by the application of a comparatively much smaller force

D. All of the above

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4

Mechanical efficiency of a centrifugal pump is the ratio of

A. Energy available at the impeller to the energy supplied to the pump by the prime mover

B. Actual workdone by the pump to the energy supplied to the pump by the prime mover

C. Energy supplied to the pump to the energy available at the impeller

D. Manometric head to the energy supplied by the impeller per kN of water

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4

Multistage centrifugal pumps are used to obtain

A. High discharge

B. High head

C. Pumping of viscous fluids

D. High head and high discharge

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4

The number of buckets on the periphery of a Pelton wheel is given by

A. (D/2d) + 5

B. (D/2d) + 10

C. (D/2d) + 15

D. (D/2d) + 20

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4

In a Kaplan turbine runner, the numbers of blades are generally between

A. 2 to 4

B. 4 to 8

C. 8 to 16

D. 16 to 24

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4

Francis turbine is best suited for

A. Medium head application from 24 to 180 m

B. Low head installation up to 30 m

C. High head installation above 180 m

D. All types of heads

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4

Medium specific speed of turbine implies it is

A. Propeller turbine

B. Francis turbine

C. Impulse turbine

D. Any one of the above

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4

Axial flow pump is started with its delivery valve

A. Kept fully closed

B. Kept fully open

C. Irrespective of any position

D. Kept 50% open

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4

According to fan laws, at constant speed and capacity, the pressure and power vary

A. Directly as the air or gas density

B. Inversely as square root of density

C. Inversely as density

D. As square of density