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What is the correct answer?

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 %

Correct Answer :

C. 84.8 %


Related Questions

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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

In impulse Turbine, energy available at the inlet is in the form of

A. Potential Energy

B. Strain Energy

C. Kinetic energy

D. None of these

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4

A centrifugal pump will start delivering liquid only when the pressure rise in the impeller is equal to the

A. Kinetic head

B. Velocity head

C. Manometric head

D. Static head

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4

A turbine is required to develop 1500 kW at 300 r.p.m. under a head of 150 m. Which of the following turbine should be used?

A. Pelton wheel with one nozzle

B. Pelton wheel with two or more nozzles

C. Kaplan turbine

D. Francis turbine

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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 %

What is the correct answer?

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 is not a reaction turbine?

A. Fourneyron turbine

B. Journal turbine

C. Thomson's turbine

D. Pelton wheel

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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

The power developed by a turbine is (where H = Head of water under which the turbine is working)

A. Directly proportional to H1/2

B. Inversely proportional to H1/2

C. Directly proportional to H3/2

D. Inversely proportional to H3/2

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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

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

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 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

A turbine develops 10000 kW under a head of 25 metres at 135 r.p.m. Its specific speed is

A. 175.4 r.p.m.

B. 215.5 r.p.m.

C. 241.5 r.p.m.

D. 275.4 r.p.m

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4

A ship with jet propulsion draws water through inlet orifices at right angles to the direction of its motion. The propelling force of the jet is (where a = Area of the jet, Vr = Relative velocity of the jet and ship = V + v, v = Velocity of the ship, and V = Velocity of the jet issuing from the ship)

A. waVr /g × (Vr + v)

B. waVr /g × (Vr - v)

C. waVr /g × (Vr + v)²

D. waVr /g × (Vr - v)²

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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

Power required to drive a centrifugal pump is directly proportional to ________ of its impeller.

A. Diameter

B. Square of diameter

C. Cube of diameter

D. Fourth power of diameter

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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 turbine pump is basically a centrifugal pump equipped additionally with

A. Adjustable blades

B. Backward curved blades

C. Vaned diffusion casing

D. Inlet guide blades

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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

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 specific speed of a turbine is the speed of an imaginary turbine, identical with the given turbine, which

A. Delivers unit discharge under unit head

B. Delivers unit discharge under unit speed

C. Develops unit power under unit head

D. Develops unit power under unit speed

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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

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

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 %

What is the correct answer?

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

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

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

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

An impulse turbine is used for

A. Low head of water

B. High head of water

C. Medium head of water

D. High discharge