Engineering Thermodynamics MCQs

Question 1

The compression ratio for Diesel engines is

Accepted Answer

15 to 20

Answer

5 to 8

Answer

3 to 6

Answer

20 to 30

Question 2

The efficiency of the Carnot cycle is (where T1 and T2 = Highest and lowest temperature during the cycle)

Accepted Answer

$$1 - \frac{{{{	ext{T}}_2}}}{{{{	ext{T}}_1}}}$$

Answer

$$\frac{{{{	ext{T}}_1}}}{{{{	ext{T}}_2}}} - 1$$

Answer

$$1 - \frac{{{{	ext{T}}_1}}}{{{{	ext{T}}_2}}}$$

Answer

$$1 + \frac{{{{	ext{T}}_2}}}{{{{	ext{T}}_1}}}$$

Question 3

One Joule (J) is equal to

Accepted Answer

1 N-m

Answer

1 kN-m

Answer

10 kN-m/s

Answer

10 N-m/s

Question 4

Reversed joule cycle is called

Accepted Answer

Bell Coleman cycle

Answer

Carnot cycle

Answer

Rankine cycle

Answer

Brayton cycle

Question 5

The entropy __________ in an irreversible cyclic process.

Accepted Answer

Increases

Answer

Remains constant

Answer

Decreases

Answer

None of these

Question 6

The pressure of a gas in terms of its mean kinetic energy per unit volume 'E' is equal to

Accepted Answer

$$\frac{{2{	ext{E}}}}{3}$$

Answer

$$\frac{{	ext{E}}}{3}$$

Answer

$$\frac{{	ext{E}}}{2}$$

Answer

$$\frac{{3{	ext{E}}}}{4}$$

Question 7

The efficiency of Diesel cycle approaches to Otto cycle efficiency when

Accepted Answer

Cut-off is zero

Answer

Cut-off is decreased

Answer

Cut-off is constant

Answer

Cut-off is increased

Question 8

The heat energy stored in the gas and used for raising the temperature of the gas is known as

Accepted Answer

Internal energy

Answer

External energy

Answer

Kinetic energy

Answer

Molecular energy

Question 9

According to kinetic theory of gases, the velocity of molecules __________ with the increase in temperature.

Accepted Answer

Increases

Answer

Remains constant

Answer

Decreases

Answer

None of these