# Mechanical Engineering - Thermodynamics - Discussion

Discussion Forum : Thermodynamics - Section 2 (Q.No. 15)
15.
During which of the following process does heat rejection takes place in Carnot cycle?
Isothermal expansion
Isentropic expansion
Isothermal compression
Isentropic compression
Explanation:
No answer description is available. Let's discuss.
Discussion:
28 comments Page 1 of 3.

Cherinet mathewos said:   7 months ago
Isothermal expansion should be the right answer.
(1)

Sushil Dumka said:   3 years ago
Answer should be A, Isothermal expansion.
(1)

Ajay said:   3 years ago
An isothermal expansion process is the heat rejection process.

Anup Singh Biswakarma said:   5 years ago
To maintain constant temperature during isothermal expansion, heat is absorbed by the system as the temperature tends to drop on increase in volume of gas. Also heat is rejected on isothermal compression as to maintain constant temperature because on compression the temperature tends to rise.

Nitin Jadhav said:   5 years ago
The answer is correct. Heat rejection takes place after isentropic expansion and during this heat rejection pressure increases but at a constant temperature so isothermal compression is the correct answer.

Kamlesh said:   5 years ago
Given answer is correct. Heat is rejected at isothermal compression.

Sandeep sahu said:   6 years ago

In isothermal expansion (1-2), the heat is added or absorb at a hot temp. While in isothermal compression (3-4) heat is rejected at cold temp.

Rajender said:   6 years ago
In the isothermal compression of a gas there is work done on the system to decrease the volume and increase the pressure. Doing work on the gas increases the internal energy and will tend to increase the temperature. To maintain the constant temperature, energy must leave the system as heat and enter the environment.

Nayan Gogoi said:   6 years ago
Heat is added at isothermal expansion.

Heat is rejected at Isothermal compression.

The given Answer is absolutely correct.

ABHISHEK said:   7 years ago
Iso-thermal compression: heat is being rejected.

Iso-thermal expansion: heat is being added into the system.