Question

Two liters of an ideal gas at a pressure of 10 atm expands isothermally into a vacuum until its total volume is 10 liters. The heat absorbed during the process is:

• A. 0
• B. 2
• C. 4
• D. 6

Hint:

In free expansion into a vacuum, the system does no work, and internal energy remains unchanged, so heat transfer (Q) is zero.

Answer 1

The Correct Option is A

For an isothermal free expansion of an ideal gas:
\[\Delta U = 0, \quad Q = \Delta U + W\]
Since $W = 0$ (no external pressure in a vacuum), the heat absorbed is:
\[Q = 0\]