Questions and answers for exam Preparation

MCQs

Total Questions : 1935 | Page 20 of 194 pages

Question 191. Which of the following statement is correct?

The efficiency of steam turbines is greater than steam engines
A flywheel is a must for steam turbine
The turbine blades do not change the direction of steam issuing from the nozzle
The pressure of steam, in reaction turbines, is increased in fixed blades as well as in moving blades

Discuss Question

Answer: Option A. -> The efficiency of steam turbines is greater than steam engines

Question 192. Which of the following statement is correct?

The expansion of steam in a nozzle follows Rankine cycle
The friction in the nozzle increases the dryness fraction of steam
The pressure of steam at throat is called critical pressure
All of the above

Discuss Question

Answer: Option D. -> All of the above

Question 193. Which of the following statement is correct?

Lancashire boiler is a fire tube boiler
Fire tube boilers are internally fired
Babcock and Wilcox boiler is a water tube boiler
All of the above

Discuss Question

Answer: Option D. -> All of the above

Question 194. Which of the following statement is correct?

A horizontal steam engine requires less floor area than a vertical steam engine
The steam pressure in the cylinder is not allowed to fall below the atmospheric pressure
The compound steam engines are generally non-condensing steam engines
All of the above

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Answer: Option B. -> The steam pressure in the cylinder is not allowed to fall below the atmospheric pressure

Question 195. The change in internal energy in steam engines equals to

Work done during the Rankine cycle
Work done during compression
Work done during adiabatic expansion
Change in enthalpy

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Answer: Option A. -> Work done during the Rankine cycle

Question 196. Which of the following statement is correct?

A fire tube boiler occupies less space than a water tube boiler, for a given power
Steam at a high pressure and in large quantities can be produced with a simple vertical boiler
A simple vertical boiler has one fire tube
All of the above

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Answer: Option C. -> A simple vertical boiler has one fire tube

Question 197. Spontaneous combustion is a phenomenon in which

All the fuel burns instantaneously producing high energy release
Fuel burns with less air
Coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal
Explosion in furnace

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Answer: Option C. -> Coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal

Question 198. The actual vacuum in a condenser is equal to

Barometric pressure + actual pressure
Barometric pressure - actual pressure
Gauge pressure + atmospheric pressure
Gauge pressure - atmospheric pressure

Discuss Question

Answer: Option B. -> Barometric pressure - actual pressure

Question 199. If partial pressure of air and steam be ‘pa’ and ‘ps’ respectively in a condenser, then according to Dalton's law, the pressure in condenser is equal to