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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

Correct Answer :

C. Q = π.D.bf.V


Related Questions

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4

The unit speed of the turbine runner is

A. N/√H

B. N/H

C. N/H3/2

D. N/H²

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4

Centrifugal 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

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

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

Which of the following statement is correct as regard to water wheels?

A. They have slow speeds

B. They are suitable even for low water heads

C. They give constant efficiency, even if the discharge is not constant

D. All of the above

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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 Thomson's turbine is __________ reaction turbine.

A. An axial flow

B. An inward flow

C. An outward flow

D. A mixed flow

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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

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

In a centrifugal pump, the liquid enters the pump

A. At the top

B. At the bottom

C. At the canter

D. From sides

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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

In a centrifugal pump, the regulating valve is provided on the

A. Casing

B. Delivery pipe

C. Suction pipe

D. Impeller

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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

The efficiency of a hydraulic press is given by (where W = Weight lifted by ram, P = Force applied on plunger, A = Area of ram, and a = Area of plunger)

A. (W/p) × (A/a)

B. (p/W) × (a/A)

C. (W/p) × (a/A)

D. (p/W) × (A/a)

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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

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

Reciprocating pumps are no more to be seen in industrial applications (in comparison to centrifugal pumps) because of

A. High initial and maintenance cost

B. Lower discharge

C. Lower speed of operation

D. Necessity of air vessel

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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 ratio of actual work available at the turbine to the energy imparted to the wheel is known as ________ efficiency.

A. Hydraulic

B. Mechanical

C. Overall

D. None of these

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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

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

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

A. Centrifugal pump

B. Reciprocating pump

C. Jet pump

D. Airlift pump

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4

A hydraulic accumulator 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

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

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

A. 4

B. 6

C. 8

D. 12

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4

Slip of a reciprocating pump is defined as the

A. Ratio of actual discharge to the theoretical discharge

B. Sum of actual discharge and the theoretical discharge

C. Difference of theoretical discharge and the actual discharge

D. Product of theoretical discharge and the actual discharge

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4

According to fan laws, for fans having constant wheel diameter, the air or gas capacity 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 jet ratio is defined as the ratio of the

A. Diameter of jet to the diameter of Pelton wheel

B. Velocity of jet to the velocity of Pelton wheel

C. Diameter of Pelton wheel to the diameter of jet

D. Velocity of Pelton wheel to the velocity of jet

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4

The optimum value of vane exit angle for a centrifugal pump impeller is

A. 10-15°

B. 20-25°

C. 30-40°

D. 50-60°