Q 11-11-149JEE MainJEE Main 2019 (10 Jan, Shift 2)Easy
Half mole of an ideal monoatomic gas is heated at a constant pressure of $1\ \text{atm}$ from $20^\circ\text{C}$ to $90^\circ\text{C}$. Work done by the gas is (Gas constant $R = 8.21\ \text{J mol}^{-1}\text{K}^{-1}$)
Answer: (C) $291\ \text{J}$
At constant pressure $W = P\Delta V = nR\Delta T$:
$$W = 0.5\times8.21\times70 \approx 287\ \text{J}$$
The closest option is $291\ \text{J}$.
Solution by Sreeraj P, M.Sc Physics