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4

The discharge through a reaction turbine with increase in unit speed

A. Increases

B. Decreases

C. Remain unaffected

D. First increases and then decreases

Correct Answer :

B. Decreases


Related Questions

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4

In a centrifugal pump casing, the flow of water leaving the

A. Radial

B. Axial

C. Centrifugal

D. Vortex

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4

In order to avoid cavitation in centrifugal pumps

A. The suction pressure should be high

B. The delivery pressure should be high

C. The suction pressure should be low

D. The delivery pressure should be low

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4

Low 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

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

Delivery head of a centrifugal pump is

A. Directly proportional to N

B. Inversely proportional to N

C. Directly proportional to N²

D. Inversely proportional to N²

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4

A hydraulic intensifier normally consists of

A. Two cylinders, two rams and a storage device

B. A cylinder and a ram

C. Two coaxial rams and two cylinders

D. A cylinder, a piston, storage tank and control valve

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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 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

Indicator diagram of a reciprocating pump is a graph between

A. Flow vs. swept volume

B. Pressure in cylinder vs. swept volume

C. Flow vs. speed

D. Pressure vs. speed

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4

Head developed by a centrifugal pump depends on

A. Impeller diameter

B. Speed

C. Fluid density

D. Both (A) and (B) above

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4

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

A. Centrifugal pump

B. Reciprocating pump

C. Jet pump

D. Air lift pump

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4

When a piping system is made up primarily of friction head and very little of vertical lift, then pump characteristics should be

A. Horizontal

B. Nearly horizontal

C. Steep

D. First rise and then fall

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4

The overall efficiency for a Pelton wheel lies between

A. 0.50 to 0.65

B. 0.65 to 0.75

C. 0.75 to 0.85

D. 0.85 to 0.90

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4

For very high discharge at low pressure such as for flood control and irrigation applications, following type of pump is preferred

A. Centrifugal

B. Axial flow

C. Reciprocating

D. Mixed flow

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4

Which of the following statement is correct?

A. The centrifugal pump is suitable for large discharge and smaller heads.

B. The centrifugal pump requires less floor area and simple foundation as compared to reciprocating pump.

C. The efficiency of centrifugal pump is less as compared to reciprocating pump.

D. All of the above

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4

The force exerted by a jet of water (in a direction normal to flow) impinging on a fixed plate inclined at an angle θ with the jet is

A. waV/2g × sinθ

B. waV/g × sinθ

C. waV²/2g × sin2θ

D. waV²/g × sinθ

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4

The hydraulic efficiency of an impulse turbine is the

A. Ratio of the actual power produced by the turbine to the energy actually supplied by the turbine

B. Ratio of the actual work available at the turbine to the energy imparted to the wheel

C. Ratio of the work done on the wheel to the energy of the jet

D. None of the above

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4

Low specific speed of a pump implies it is

A. Centrifugal pump

B. Mixed flow pump

C. Axial flow pump

D. None of the above

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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

For starting an axial flow pump, its delivery valve should be

A. Closed

B. Open

C. Depends on starting condition and flow desired

D. Could be either open or closed

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4

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

A. Rotational flow

B. Radial

C. Forced spiral vortex flow

D. Spiral vortex flow

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4

The static head of a centrifugal pump is equal to the ________ of suction head and delivery head.

A. Product

B. Difference

C. Sum

D. None of these

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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

One horsepower is equal to

A. 102 watts

B. 75 watts

C. 550 watts

D. 735 watts

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4

Braking jet in an impulse turbine is used

A. To break the jet of water

B. To bring the runner to rest in a short time

C. To change the direction of runner

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 power of the wheel is

A. 0.25 kW

B. 0.75 kW

C. 1.75 kW

D. 3.75 kW

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4

Geometric similarity is said to exist between the model and the prototype, if both of them

A. Have identical velocities

B. Are equal in size and shape

C. Are identical in shape, but differ only in size

D. Have identical forces

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4

Saving of work done and power by fitting an air vessel to double 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

Which of the following pump is suitable for small discharge and high heads?

A. Centrifugal pump

B. Axial flow pump

C. Mixed flow pump

D. Reciprocating pump

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4

Which of the following turbine is preferred for a specific speed of 60 to 300 r.p.m.?

A. Pelton wheel

B. Francis turbine

C. Kaplan turbine

D. None of these