Question

In a given process for an ideal gas, dW = 0 and dQ < 0, then for the gas:

• A. The volume will decrease
• B. The volume will increase
• C. The pressure will remain constant
• D. The internal energy will decrease

Answer 1

The correct option is D The internal energy will decrease

From the First law of thermodynamics,
dU = dQ + dW
$\because$ dQ < 0 and $\because$ dW = 0 $\Rightarrow$ dU < 0
Hence, internal energy decreases.