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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.

Correct Answer :

B. 20 r.p.m.


Related Questions

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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

Medium specific speed of a pump implies it is

A. Centrifugal pump

B. Mixed flow pump

C. Axial flow pump

D. Any one of the above

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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

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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

High specific speed of a pump implies it is

A. Centrifugal pump

B. Mixed flow pump

C. Axial flow pump

D. Any one of the above

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4

The relation between hydraulic efficiency (ηh), mechanical efficiency (ηm) and overall efficiency (ηo) is

A. ηh = ηo × ηm

B. ηm = ηm × ηh

C. ηo = ηh × ηm

D. None of these

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4

The flow ratio of Francis turbine is defined as the ratio of the

A. Velocity of flow at inlet to the theoretical jet velocity

B. Theoretical velocity of jet to the velocity of flow at inlet

C. Velocity of runner at inlet to the velocity of flow at inlet

D. None of the above

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4

Discharge (Q) of a centrifugal pump is given by (where D = Diameter of impeller at inlet, b = Width of impeller at inlet, and Vf = Velocity of flow at inlet)

A. Q = π.D.Vf

B. Q = π.b.Vf

C. Q = π.D.bf.V

D. Q = D.b.Vf

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4

In a Francis 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

For centrifugal pump impeller, the maximum value of the vane exit angle is

A. 10° to 15°

B. 15° to 20°

C. 20° to 25°

D. 25° to 30°

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4

Pressure intensifier increases the pressure in proportion to

A. Ratio of diameters

B. Square of ratio of diameters

C. Inverse ratio of diameters

D. Square of inverse ratio of diameters

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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

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

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

The ratio of the normal force of jet of water on a plate inclined at an angle of 30° as compared to that when the plate is normal to jet, is

A. 1/√2

B. 1/2

C. 1

D. √2

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4

For 450 m head of water, _________ shall be used.

A. Pelton wheel

B. Kaplan turbine

C. Francis turbine

D. None of these

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4

Francis, Kaplan and propeller turbines fall under the category of

A. Impulse turbines

B. Reaction turbines

C. Axial flow turbines

D. Mixed flow turbines

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4

Which place in hydraulic turbine is most susceptible for cavitations?

A. Inlet of draft rube

B. Blade inlet

C. Guide blade

D. Penstock

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4

Which of the following is not an impulse turbine?

A. Girad turbine

B. Turgo turbine

C. Pelton wheel

D. Kaplan turbine

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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 hydraulic efficiency of a reaction turbine, is the ratio of

A. Power produced by the turbine to the energy actually supplied by the turbine

B. Actual work available at the turbine to energy imparted to the wheel

C. Workdone on the wheel to the energy (or head of water) actually supplied to the turbine

D. None of the above

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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 maximum hydraulic efficiency of an impulse turbine is (where φ = Angle of blade tip at outlet)

A. (1 + cos φ)/2

B. (1 - cos φ)/2

C. (1 + sin φ)/2

D. (1 - sin φ)/2

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4

The angle of taper on draft tube is

A. Greater than 15°

B. Greater than 8°

C. Greater than 5°

D. Less than 8°

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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

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

One horsepower is equal to

A. 102 watts

B. 75 watts

C. 550 watts

D. 735 watts

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4

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

A. Centrifugal pump

B. Axial flow pump

C. Mixed flow pump

D. Reciprocating pump

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4

The cavitation in a hydraulic machine

A. Causes noise and vibration of various parts

B. Reduces the discharge of a turbine

C. Causes sudden drop in power output and efficiency

D. All of the above

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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