1. Use the first law of thermodynamics

For the gas, $Q=\Delta U + W$ where:

• $Q = 48\,\text{J}$ is the heat supplied,
• $\Delta U$ is the change in internal energy,
• $W$ is the work done by the gas.

2. Find change in internal energy for helium

Helium is a monoatomic ideal gas, so for $n$ moles: $\Delta U = n C_V \Delta T$ with $C_V = \frac{3R}{2}$

Given:

• $n=1$
• $R=8.3\,\text{J mol}^{-1}\text{K}^{-1}$
• $\Delta T = 2^\circ C = 2\,\text{K}$

Thus, $\Delta U = 1 \times \frac{3}{2} \times 8.3 \times 2$ $\Delta U = 3 \times 8.3 = 24.9\,\text{J}$

3. Calculate work done

From $W = Q - \Delta U$ we get $W = 48 - 24.9 = 23.1\,\text{J}$

4. Match with options

$W = 23.1\,\text{J}$ So the correct option is A.