250+ TOP MCQs on Engine Heat Transfer and Answers

IC Engines Multiple Choice Questions on “Engine Heat Transfer”.

1. ____________ is the transfer of heat from one part of a substance to another part of the same substance.
a) Convection
b) Conduction
c) Radiation
d) None of the mentioned
Answer: b
Clarification: Conduction is defined as the transfer of heat from one part of a substance to another part of the same substance while convection is defined as the transfer of heat within a fluid by mixing of one portion of the fluid with another.

2. ____________ is the transfer of heat within a fluid by mixing of one portion of fluid with another.
a) Convection
b) Conduction
c) Radiation
d) None of the mentioned
Answer: a
Clarification: Convection is defined as the transfer of heat within a fluid by mixing of one portion of fluid with another while conduction is defined as the transfer of heat from one part of a substance to another part of the same substance.

3. ____________ convection occurs when the fluid circulates by virtue of the natural differences in densities of hot and cold fluids.
a) Forced
b) Natural
c) Unpredictable
d) None of the mentioned
Answer: b
Clarification: None.

4. In natural convection, the denser portions of the fluid move downward because of the greater force of gravity, as compared with the force on the less dense.
a) True
b) False
Answer: a
Clarification: None.

5. When the work is done to blow or pump the fluid, it is said to be ____________ convection.
a) natural
b) forced
c) unpredictable
d) none of the mentioned
Answer: b
Clarification: When the work is done to blow or pump the fluid, it is said to be forced convection while natural convection occurs when the fluid circulates by virtue of the natural differences in densities of hot and cold fluids.

6. ____________ is the transfer of heat through space or matter by means other than conduction or convection.
a) Forced
b) Natural
c) Radiation
d) None of the mentioned
Answer: c
Clarification: Radiation is the transfer of heat through space or matter by means other than conduction or convection and when the work is done to blow or pump the fluid, it is said to be forced convection while natural convection occurs when the fluid circulates by virtue of the natural differences in densities of hot and cold fluids.

7. In the case of air cooling, the boundary layer as on the gas side offers great resistance, but the effect of this is compensated largely by providing more surface areas by way of cooling pins.
a) True
b) False
Answer: a
Clarification: Yes, in case of air cooling, the boundary layer as on the gas side offers great resistance, but the effect of this is compensated largely by providing more surface areas by way of cooling pins.

8. In the case of water cooling, there no boundary layer of the liquid coolant on the outside of the cylinder wall.
a) True
b) False
Answer: b
Clarification: Actually, in the case of water cooling, there is also a boundary layer of the liquid coolant on the outside of the cylinder wall.

9. When the spark advance is same as the optimum value the heat rejected to cooling system is increased.
a) True
b) False
Answer: b
Clarification: In fact, when the spark advance is different from the optimum value the heat rejected to the cooling system is increased.

10. Gas temperature remains at a higher average with increased speed.
a) True
b) False
Answer: a
Clarification: None.