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4

The discharge through a reaction turbine ________ with the increase in unit speed.

A. Decreases

B. Increases

C. Remain same

D. None of these

Correct Answer :

A. Decreases


Related Questions

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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

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

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

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

Discharge of a centrifugal pump is

A. Directly proportional to diameter of its impeller

B. Inversely proportional to diameter of its impeller

C. Directly proportional to (diameter)² of its impeller

D. Inversely proportional to (diameter)² of its impeller

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4

The flow rate in gear pump

A. Increases with increase in pressure

B. Decreases with increase in pressure

C. More or less remains constant with increase in pressure

D. Unpredictable

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4

The gross or total head of the turbine is the ________ of the water levels at the head race and tail race.

A. Sum

B. Difference

C. Product

D. None of these

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4

The power produced by the reaction turbine is ________ to the head of water.

A. Directly proportional

B. Inversely proportional

C. 4th power

D. None of these

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4

By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. This saving in case of a single acting reciprocating pump is

A. 39.2 %

B. 48.8 %

C. 84.8 %

D. 88.4 %

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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

The undershot water wheels are those in which

A. The wheel runs entirely by the weight of water

B. The wheel runs entirely by the impulse of water

C. The wheel runs partly by the weight of water and partly by the impulse of water

D. None of the above

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4

Air vessels in reciprocating pump are used to

A. Smoothen flow

B. Reduce acceleration to minimum

C. Increase pump efficiency

D. Save pump from cavitations

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4

According to fan laws, at constant weight of air or gas, the speed, capacity and pressure 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

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4

The runaway speed of a hydraulic turbine is the speed

A. At full load

B. At which there will be no damage to the runner

C. Corresponding to maximum overload permissible

D. At which the turbine will run freely without load

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4

The type of centrifugal pump preferred for a specific speed of 20 r.p.m. is

A. Slow speed pump with radial flow at outlet

B. Medium speed pump with radial flow at outlet

C. High speed pump with radial flow at outlet

D. High speed pump with axial flow at outlet

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4

The specific speed of a hydraulic turbine depends upon

A. Speed and power developed

B. Discharge and power developed

C. Speed and head of water

D. Speed, power developed and head of water

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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

Power required (in watts) to drive a centrifugal pump is (where Hm = Manometric head in metres, w = Specific weight in N/m3, Q = Discharge of the pump in m3/s, and ηo = Overall efficiency of the pump)

A. (w Hm) / (Q × ηo)

B. (w Hm Q) / ηo

C. (w Q) / (Hm × ηo)

D. (w Q ηo) / Hm

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4

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

A. Rectilinear flow

B. Radial flow

C. Free vortex motion

D. Forced vortex

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4

Which of the following turbine is preferred for 0 to 25 m head of water?

A. Pelton wheel

B. Kaplan turbine

C. Francis turbine

D. None of these

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4

The speed ratio in case of Francis turbine varies from

A. 0.15 to 0.3

B. 0.4 to 0.5

C. 0.6 to 0.9

D. 1 to 1.5

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4

The discharge of a double acting reciprocating pump is (where L = Length of stroke, A = Cross-sectional area of piston, and N = Speed of crank in r.p.m.)

A. L.A.N

B. 2 L.A.N

C. (L.A.N)/60

D. (2 L.A.N)/60

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4

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

A. No flow will take place

B. Cavitation will be formed

C. Efficiency will be low

D. Excessive power will be consumed

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

A. Installing the turbine below the tail race level

B. Using stainless steel runner of the turbine

C. Providing highly polished blades to the runner

D. All of the above

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4

High specific speed of turbine implies it is

A. Propeller turbine

B. Francis turbine

C. Impulse turbine

D. None of the above

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4

By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. The saving in case of a double acting reciprocating pump is

A. 39.2 %

B. 48.8 %

C. 84.8 %

D. 88.4 %

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4

Dynamic 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. None of the above

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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

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