Physics Thermodynamics SZABMU 2022
PMDC Verified Question 36 of 54
The internal energy of a system during an isothermal process:
A
Remain constant
B
Decreases
C
Become zero
D
Increases
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Remain constant
1. Concept:

For an ideal gas, internal energy is purely a function of its absolute kinetic temperature. If the temperature does not change, the internal kinetic energy cannot change.

2. Formula:

$$\Delta U = n C_v \Delta T$$

3. Solution:

  • An isothermal process is characterized by \(\Delta T = 0\).


  • Plugging this into the internal energy equation yields \(\Delta U = 0\).


  • Because the change is zero, the total internal energy remains constant throughout the entire process.


4. Why other options are incorrect:

Internal energy cannot decrease or increase unless the temperature changes. It cannot become zero unless the gas reaches absolute zero (0 K), which is not the case for a standard isothermal process.

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