Physics Question from JEE Main 2026 · 24 January, Shift 2

When $300 \, J$ of heat is given to an ideal gas with $C_p = \dfrac{7}{2}R$, its temperature rises from $20^\circ C$ to $50^\circ C$ keeping its volume constant. The mass of the gas is (approximately) _____ g. $\left(R = 8.314 \, J/mol\cdot K\right)$