In ideal gases the molecules are considered as point particles and for point particles, there is no internal excitation, no vibration and no rotation. For an ideal gas the internal energy can only be translational kinetic energy and for real gas both kinetic as well as potential energy.
JEE Main 2013 Physics, Kinetic Theory of Gases — question figure There are two identical chambers, completely thermally insulated from surroundings.…
JEE Main 2013 — Physics Thermodynamics
2013mcqmedium
There are two identical chambers, completely thermally insulated from surroundings. Both chambers have a partition wall dividing the chambers in two compartments. Compartment 1 is filled with an ideal gas and Compartment 3 is filled with a real gas. Compartments 2 and 4 are vacuum. A small hole (orifice) is made in the partition walls and the gases are allowed to expand in vacuum. Statement−1: No change in the temperature of the gas takes place when ideal gas expands in vacuum. However, the temperature of real gas goes down (cooling) when it expands in vacuum. Statement−2: The internal energy of an ideal gas is only kinetic. The internal energy of a real gas is kinetic as well as potential.
Official previous-year question
Held on 9 Apr 2013 · Verified 6 Jul 2026.
Options
- A
Statement-1 is false and Statement-2 is true.
- B
Statement-1 and Statement-2 both are true. Statement-2 is the correct explanation of Statement-1.
- C
Statement-1 is true and Statement- 2 is false.
- D
Statement-1 and Statement-2 both are true. Statement-2 is not correct explanation of Statement-1.
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