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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

Correct Answer :

B. 6


Related Questions

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4

Power required (in watts) to drive a centrifugal pump is (where Hm = Manometric head in metres, w = Specific weight in N/m3, Q = Discharge of the pump in m3/s, and ηo = Overall efficiency of the pump)

A. (w Hm) / (Q × ηo)

B. (w Hm Q) / ηo

C. (w Q) / (Hm × ηo)

D. (w Q ηo) / Hm

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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

Which of the following statement is wrong?

A. The reaction turbines are used for low head and high discharge.

B. The angle of taper on draft tube is less than 8°.

C. An impulse turbine is generally fitted slightly above the tail race.

D. A Francis turbine is an impulse turbine.

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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

In a Kaplan 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 centrifugal pump preferred for a specific speed between 80 to 160 r.p.m. is

A. Slow speed with radial flow at outlet

B. Medium speed with radial flow at outlet

C. High speed with radial flow at outlet

D. High speed with mixed flow at outlet

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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

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

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

A hydraulic accumulator is a device used to store ________ energy which may be supplied to a machine later on.

A. Strain

B. Pressure

C. Kinetic

D. None of these

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4

For small discharge at high pressure, following pump is preferred

A. Centrifugal

B. Axial flow

C. Mixed flow

D. Reciprocating

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4

The flow rate in gear pump

A. Increases with increase in pressure

B. Decreases with increase in pressure

C. More or less remains constant with increase in pressure

D. Unpredictable

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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

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4

Which of the following pump is suitable for small discharge and high heads?

A. Centrifugal pump

B. Axial flow pump

C. Mixed flow pump

D. Reciprocating pump

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4

According to fan laws, at constant pressure, the speed capacity and power vary

A. Directly as the air or gas density

B. Inversely as square root of density

C. Inversely as density

D. As square of density

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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

Multistage centrifugal pumps are used to obtain

A. High discharge

B. High head

C. Pumping of viscous fluids

D. High head and high discharge

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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

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 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 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

According to fan laws, for fans having constant wheel diameter, the pressure 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

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

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 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

Low 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

A hydraulic coupling belongs to the category of

A. Power absorbing machines

B. Power developing machines

C. Energy transfer machines

D. Energy generating machines

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4

If the ratios of all the corresponding linear dimensions 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

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

Hydraulic accumulator is used for

A. Accumulating oil

B. Supplying large quantities of oil for very short duration

C. Generally high pressures to operate hydraulic machines

D. Supplying energy when main supply fails