Heat is given to an ideal gas in an isothermal process.
A. Internal energy of the gas will decrease.
B. Internal energy of the gas will increase.
C. Internal energy of the gas will not change.
D. The gas will do positive work.
E. The gas will do negative work.
Choose the correct answer from the options given below :

Question

Heat is given to an ideal gas in an isothermal process.

A. Internal energy of the gas will decrease.

B. Internal energy of the gas will increase.

C. Internal energy of the gas will not change.

D. The gas will do positive work.

E. The gas will do negative work.

Choose the correct answer from the options given below :

TestHub · Accepted Answer

From the first law of thermodynamics, heat supplied to the system $Q$ , change in internal energy of the system $∆ U$ and work done by the system $W$ are related as:

$Q = ∆ U + W$

Since the process is isothermal, the temperature of the system is constant and therefore $∆ U = 0$ (i.e., internal energy is constant).

$\Rightarrow Q = W$

As heat is supplied to the system, $Q$ is positive and therefore $W$ is positive i.e., gas will do positive work.

Hence, correct options are C and D.

Physics - Heat & Thermo Question with Solution | TestHub

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