Physics Question from JEE Main 2026 · 23 January, Shift 2

The internal energy of a monoatomic gas is $3nRT$. One mole of helium is kept in a cylinder having internal cross-sectional area $17 \, \text{cm}^2$ and fitted with a light movable frictionless piston. The gas is heated slowly by supplying $126 \, \text{J}$ of heat. If the temperature rises by $4^\circ\text{C}$, then the piston will move _____ cm.

(atmospheric pressure $= 10^5 \, \text{Pa}$)