# Thermodynamics Questions and Answers – Cyclic Heat Engine

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This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on “Cyclic Heat Engine”.

1. The first law of thermodynamics doesn’t tell us whether a thermodynamic process is feasible or not.
a) true
b) false

Explanation: The second law of thermodynamics provides criterion as to the probability of a process.

2. According to Joule’s experiments,
a) heat can be completely converted into work
b) work can be completely converted into heat
c) both heat and work are completely interchangeable
d) all of the mentioned

Explanation: Work transfer -> internal energy increase -> heat transfer.

3. Which of the following is true?
a) work is a high grade energy
b) heat is a low grade energy
c) complete conversion of low grade energy into high grade energy in a cycle is impossible
d) all of the mentioned

Explanation: These facts are in accordance with Joule’s work and underlies the work of Carnot.

4. In a cyclic heat engine there is
a) net heat transfer to the system and net work transfer from the system
b) net heat transfer from the system and net work transfer to the system
c) depends on the conditions of cycle
d) none of the mentioned

Explanation: This is the basic concept of cycle heat engine.

5. Boiler, turbine, condenser and pump together constitute a heat engine.
a) true
b) false

Explanation: It is an example for a cyclic heat engine.

6. In a heat engine cycle, which of the following process occurs?
a) heat is transferred from furnace to boiler
b) work is produced in turbine rotor
c) steam is condensed in condenser
d) all of the mentioned

Explanation: These are the basic processes occurring in a heat engine cycle comprising of furnace, boiler condenser and a turbine.

7. The function of a heat engine cycle is to _____ continuously at the expense of _____ to the system.
a) heat input, produce work
b) produce work, heat input
c) can be both of the mentioned
d) none of the mentioned

Explanation: Net work and heat input are of primary interest in a cycle.

8. Efficiency of a heat engine is defined as
a) total heat output / net work input
b) total heat input / net work output
c) net work output / total heat input
d) net work input / total heat output

Explanation: Basic definition of efficiency.

9. A thermal energy reservoir is a large body of
a) small heat capacity
b) large heat capacity
c) infinite heat capacity
d) none of the mentioned

10. Processes inside a thermal energy reservoir are quasi-static.
a) true
b) false

Explanation: The changes taking place in TER are very slow and minute.

11. A TER which transfers heat to system is called ____ and one which receives heat is called ____
a) source, sink
b) sink, source
c) sink, sink
d) source, source

Explanation: A source transfers heat while a sink receives heat.

12. Which if the following statements are true for a mechanical energy reservoir(MER)?
a) it is a large body enclosed by an adiabatic impermeable wall
b) stores work as KE or PE
c) all processes within an MER are quasi-static
d) all of the mentioned 