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4

The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and hd = Enthalpy or heat drop during expansion of steam in a nozzle)

A. V = 44.72 hd K

B. V = 44.72 K hd

C. V = 44.72 K hd

D. V = 44.72 K hd

Correct Answer :

C. V = 44.72 K hd


Related Questions

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4

The fire tubes in a Cochran boiler are

A. Horizontal

B. Vertical

C. Inclined

D. None of these

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4

The diagram factor is the ratio of the

A. Area of the actual indicator diagram to the area of theoretical indicator diagram

B. Actual workdone per stroke to the theoretical workdone per stroke

C. Actual mean effective pressure to the theoretical mean effective pressure

D. Any one of the above

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4

Reheating of steam in a turbine

A. Increases the workdone through the turbine

B. Increases the efficiency of the turbine

C. Reduces wear on the blades

D. All of these

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4

The ultimate analysis of fuel lists

A. Various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as percents by volume

B. Various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as percents by weight

C. Fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash

D. Fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash

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4

In case of non-condensing steam engines, the pressure of steam in the cylinder during exhaust stroke is _________ the condenser pressure.

A. Equal to

B. Lower than

C. Higher than

D. None of these

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4

In turbines, the fluid undergoes a continuous steady flow process and the speed of flow is

A. Low

B. Very low

C. High

D. Very high

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4

In a throttling process

A. Heat transfer takes place

B. Work is done by the expanding steam

C. Internal energy of steam changes

D. None of the above

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4

The nozzle efficiency is the ratio of

A. Workdone on the blades to the energy supplied to the blades

B. Workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam

C. Energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam

D. None of the above

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4

An air preheater is installed

A. Before the economiser

B. Before the superheater

C. Between the economiser and chimney

D. None of these

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4

In a glass tube type water indicator for a boiler, one end of the tube is connected to water space and the other end is connected to

A. Water space also

B. Chimney

C. Steam space

D. Superheater

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4

Blow off cock in a boiler is used to

A. Control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required

B. Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler

C. Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit

D. Increase the temperature of saturated steam without raising its pressure

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4

Fire tube boilers are

A. Internally fired

B. Externally fired

C. Internally as well as externally fired

D. None of these

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4

The increase in pressure

A. Lowers the boiling point of a liquid

B. Raises the boiling point of a liquid

C. Does not affects the boiling point of a liquid

D. Reduces its volume

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4

The latent heat of steam with increase of pressure

A. Remain same

B. Increases

C. Decreases

D. Behaves unpredictably

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4

Which of the following boilers is best suited to meet fluctuating demands?

A. Babcock and Wilcox

B. Locomotive

C. Lancashire

D. Cochran

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4

Water tube boilers are

A. Internally fired

B. Externally fired

C. Internally as well as externally fired

D. None of these

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4

Mechanical equivalent of heat for 1 kcal or Joule's equivalent is equal to

A. 421 kg.m

B. 421 kg.m

C. 539 kg.m

D. 102 kg.m

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4

When the inlet pressure of steam is equal to the exit pressure, then

A. There is a pressure drop in the nozzle

B. Fluid flows through the nozzle

C. Pressure drops and fluid flows through the nozzle

D. There is no pressure drop and fluid does not flow through the nozzle

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4

A fusible plug is fitted in small boilers in order to

A. Avoid excessive build up of pressure

B. Avoid explosion

C. Extinguish fire if water level in the boiler falls below alarming limit

D. Control steam dome

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4

Which of the following statement is correct?

A. The efficiency of steam turbines is greater than steam engines

B. A flywheel is a must for steam turbine

C. The turbine blades do not change the direction of steam issuing from the nozzle

D. The pressure of steam, in reaction turbines, is increased in fixed blades as well as in moving blades

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4

De-Laval turbines are mostly used

A. Where low speeds are required

B. For small power purposes and low speeds

C. For large power purposes

D. For small power purposes and high speeds

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4

In a reaction turbine

A. The steam is allowed to expand in the nozzle, where it gives a high velocity before it enters the moving blades

B. The expansion of steam takes place partly in the fixed blades and partly in the moving blades

C. The steam is expanded from a high pressure to a condenser pressure in one or more nozzles

D. The pressure and temperature of steam remains constant

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4

The best suited coal for chain or travelling grate stoker boiler is

A. Coking coal

B. Non-coking or free burning coal

C. Pulverised coal

D. High sulphur coal

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4

At which pressure the properties of water and steam become identical

A. 0.1 kg/cm²

B. 1 kg/cm²

C. 100 kg/cm²

D. 225.6 kg/cm²

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4

A supercritical boiler is one that operates above the pressure and temperature of following values

A. 100 kg/cm² and 540°C

B. 1 kg/cm² and 100°C

C. 218 kg/cm² abs and 373°C

D. 218 kg/cm² abs and 540°C

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4

All steam engines work on

A. Zeroth law of thermodynamics

B. First law of thermodynamics

C. Second law of thermodynamics

D. None of these

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4

Calorific value of coal is of the order of

A. 200-400 kcal/ kg

B. 800-1200 kcal/ kg

C. 2000-4000 kcal/ kg

D. 5000-8000 kcal/ kg

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4

The main object of a boiler trial is

A. To determine the generating capacity of the boiler

B. To determine the thermal efficiency of the boiler when working at a definite pressure

C. To prepare heat balance sheet for the boiler

D. All of the above

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4

Bomb calorimeter is used to determine

A. Higher calorific value at constant volume

B. Lower calorific value at constant volume

C. Higher calorific value at constant pressure

D. Lower calorific value at constant pressure

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4

Which of the following is a water tube boiler?

A. Lancashire boiler

B. Babcock and Wilcox boiler

C. Locomotive boiler

D. Cochran boiler