Engineering Thermodynamics MCQs

Question 1

When the gas is cooled at constant pressure,

Accepted Answer

Both temperature and volume decreases

Answer

Its temperature increases but volume decreases

Answer

Its volume increases but temperature decreases

Answer

Both temperature and volume increases

Question 2

The specific heat at constant volume is

Accepted Answer

The amount of heat required to raise the temperature of unit mass of gas through one degree, at constant volume

Answer

The amount of heat required to raise the temperature of unit mass of gas through one degree, at constant pressure

Answer

The amount of heat required to raise the temperature of 1 kg of water through one degree

Answer

Any one of the above

Question 3

Which of the following is the correct statement?

Accepted Answer

Irreversible engines have maximum efficiency.

Answer

All the reversible engines have the same efficiency.

Answer

All the reversible and irreversible engines have the same efficiency.

Answer

All engines are designed as reversible in order to obtain maximum efficiency.

Question 4

Which of the following is the correct statement?

Accepted Answer

For a given compression ratio, Otto cycle is more efficient than Diesel cycle

Answer

For a given compression ratio, both Otto and Diesel cycles have the same efficiency

Answer

For a given compression ratio, Diesel cycle is more efficient than Otto cycle

Answer

The efficiency of Otto or Diesel cycle has nothing to do with compression ratio

Question 5

In an isothermal process,

Accepted Answer

All of these

Answer

There is no change in temperature

Answer

There is no change in enthalpy

Answer

There is no change in internal energy

Question 6

Which is the incorrect statement about Carnot cycle?

Accepted Answer

All the heat engines are based on Carnot cycle

Answer

It is used as the alternate standard of comparison of all heat engines

Answer

It provides concept of maximising work output between the two temperature limits

Answer

All of the above

Question 7

One kilowatt is equal to

Accepted Answer

1000 N-m/s

Answer

1 N-m/s

Answer

100 N-m

Answer

1 × 106 N-m/s

Question 8

Which of the following is correct?

Accepted Answer

Absolute pressure = Gauge pressure + Atmospheric pressure

Answer

Gauge pressure = Absolute pressure + Atmospheric pressure

Answer

Atmospheric pressure = Absolute pressure + Gauge pressure

Answer

Absolute pressure = Gauge pressure - Atmospheric pressure

Question 9

Which of the following is correct?

Accepted Answer

Absolute pressure = Gauge pressure + Atmospheric pressure

Answer

Gauge pressure = Absolute pressure + Atmospheric pressure

Answer

Absolute pressure = Gauge pressure - Atmospheric pressure

Answer

Atmospheric pressure = Absolute pressure + Gauge pressure