One mole of diatomic gas having rotational modes only is kept in a cylinder with a piston system. The cross-section area of the cylinder is 4 cm$$^2$$. The gas is heated slowly to raise the temperature by 1.2 $$^\circ$$C during which the piston moves by 25 mm. The amount of heat supplied to the gas is __________ J. (Atmospheric pressure = 100 kPa, $$R = 8.3$$ J/mol. K) (Neglect mass of the piston)