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4

If a pump is handling water and is discharging a certain flow Q at a constant total dynamic head requiring a definite B.H.P., the same pump when handling a liquid of specific gravity 0.75 and viscosity nearly same as of water would discharge

A. Same quantity of liquid

B. 0.75 Q

C. Q/0.75

D. 1.5 Q

Correct Answer :

A. Same quantity of liquid


Related Questions

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4

The function of guide vanes in a reaction turbine is to

A. Allow the water to enter the runner without shock

B. Allow the water to flow over them, without forming eddies

C. Allow the required quantity of water to enter the turbine

D. All of the above

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4

The unit power developed by a turbine is (where P = Power developed by the turbine under a head of water (H).

A. P/ √H

B. P/ H

C. P/ H3/2

D. P/ H²

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4

A Pelton wheel is

A. Tangential flow impulse turbine

B. Inward flow impulse turbine

C. Outward flow impulse turbine

D. Inward flow reaction turbine

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4

In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by

A. Designing new impeller

B. Trimming the impeller size to the required size by machining

C. Not possible

D. Some other alterations in the impeller

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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

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

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

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

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

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

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

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

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

A hydraulic press is a device used

A. To store pressure energy which may be supplied to a machine later on

B. To increase the intensity of pressure of water by means of energy available from a large quantity of water at a low pressure

C. To lift larger load by the application of a comparatively much smaller force

D. All of the above

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4

The mechanical efficiency of an impulse turbine is

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

The working of which of the following hydraulic units is based on Pascal's law?

A. Air lift pump

B. Jet pump

C. Hydraulic coupling

D. Hydraulic press

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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 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

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 overall 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 the 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

Impulse turbine is generally fitted

A. At the level of tail race

B. Little above the tail race

C. Slightly below the tail race

D. About 2.5 m above the tail race to avoid cavitations.

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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

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

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

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

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

A Pelton wheel working under a constant head and discharge, has maximum efficiency when the speed ratio is

A. 0.26

B. 0.36

C. 0.46

D. 0.56

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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

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 discharge of wheel is

A. 0.25 m3/s

B. 0.5 m3/s

C. 1.5 m3/s

D. 2.5 m3/s

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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