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Current Affairs January 2024

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4

The maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship, is

A. 40 %

B. 50 %

C. 60 %

D. 80 %

Correct Answer :

B. 50 %


Related Questions

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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

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 speed of the wheel is

A. 10 r.p.m.

B. 20 r.p.m.

C. 40 r.p.m.

D. 80 r.p.m.

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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 hydraulic ram is a device used to

A. Store the energy of water

B. Increase the pressure of water

C. To lift water from deep wells

D. To lift small quantity of water to a greater height when a large quantity of water is available at a smaller height

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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 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 hydraulic efficiency of an impulse turbine is the

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

For very high discharge at low pressure such as for flood control and irrigation applications, following type of pump is preferred

A. Centrifugal

B. Axial flow

C. Reciprocating

D. Mixed flow

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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

For 450 m head of water, _________ shall be used.

A. Pelton wheel

B. Kaplan turbine

C. Francis turbine

D. None of these

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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 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

Reaction turbines are used for

A. Low head

B. High head

C. High head and low discharge

D. Low head and high discharge

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4

Specific speed for reaction turbines ranges from

A. 0 to 4.5

B. 10 to 100

C. 80 to 200

D. 250 to 300

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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

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 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

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

Slip of a reciprocating pump is negative, when

A. Suction pipe is short and pump is running at low speeds

B. Delivery pipe is long and pump is running at high speeds

C. Suction pipe is short and delivery pipe is long and the pump is running at low speeds

D. Suction pipe is long and delivery pipe is short and the pump is running at high speeds

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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

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

A. Radial

B. Axial

C. Centrifugal

D. Vortex

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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 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

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

A. Equal to

B. 1.2 times

C. 1.8 times

D. Double

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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 power produced by the reaction turbine is ________ to the head of water.

A. Directly proportional

B. Inversely proportional

C. 4th power

D. None of these

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4

Guide angle as per the aerofoil theory of Kaplan turbine blade design is defined as the angle between

A. Lift and resultant force

B. Drag and resultant force

C. Lift and tangential force

D. Lift and drag

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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

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

Overall efficiency of a centrifugal pump is the ratio of

A. Energy available at the impeller to the energy supplied to the pump by the prime mover

B. Actual workdone by the pump to the energy supplied to the pump by the prime mover

C. Energy supplied to the pump to the energy available at the impeller

D. Manometric head to the energy supplied by the impeller per kN of water