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What is the correct answer?

4

Head developed by a centrifugal pump is

A. Proportional to diameter of impeller

B. Proportional to speed of impeller

C. Proportional to diameter and speed of impeller

D. None of the above

Correct Answer :

C. Proportional to diameter and speed of impeller


Related Questions

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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 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

The width of the bucket for a Pelton wheel is generally ________ the diameter of jet.

A. Double

B. Three times

C. Four times

D. Five times

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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

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 number of buckets on the periphery of a Pelton wheel is given by

A. (D/2d) + 5

B. (D/2d) + 10

C. (D/2d) + 15

D. (D/2d) + 20

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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

The specific speed of a turbine is given by the equation

A. N√P / H3/2

B. N√P / H²

C. N√P / H5/4

D. N√P / H3

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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

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

The efficiency of jet propulsion for a ship with inlet orifices at right angles to the direction of motion of ship is given by

A. [2(Vr - v) v]/ Vr²

B. 2(Vr + v) v]/ Vr²

C. [(Vr - v) v]/ Vr

D. [(Vr + v) v]/ Vr

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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 ratio of quantity of liquid discharged per second from the pump to the quantity of liquid passing per second through the impeller is known as

A. Manometric efficiency

B. Mechanical efficiency

C. Overall efficiency

D. Volumetric efficiency

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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

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

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

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 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

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 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

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

A. Radial

B. Axial

C. Centrifugal

D. Vortex

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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

The flow 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

If the ratio's of the corresponding forces acting at corresponding points are equal, then the model and the prototype are said to have.

A. Geometric similarity

B. Kinematic similarity

C. Dynamic similarity

D. None of these

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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

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

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

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

According to fan laws, for the fans having constant wheel diameters, the power demand 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

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, the horse power required will be

A. Same

B. 0.75 B.H.P.

C. B.H.P./0.75

D. 1.5 B.H.P.