[UPSC IFoS 2024] Thermodynamics (Q18, 5M)

(i) Prove that for perfect gas the specific heat at constant pressure C_p is always greater than the specific heat at constant volume by a constant value R. (ii) Consider for hydrogen, the density at NTP is 0.0899\text{ gm/lit}, molecular weight 2.016\text{ gm} and specific heat at constant pressure 6.85\text{ cal/gm}. Calculate the specific heat of hydrogen gas at constant volume. Given : J = 4.18 \times 10^7\text{ erg}.