Question

A reversible cyclic process for an ideal gas is shown below. Here, P , V and T are pressure , volume and temperature , respectively. The thermodynamic parameters q, w, H and U are heat, work, enthalpy and internal energy, respectively.

The correct option(s) is (are)
(A) q_AC = ΔU_BC and w_AB = P₂ (V₂ – V₁)
(B) w_BC = P₂ (V₂ – V₁) and q_BC = ΔH_AC
(C) ΔH_CA < ΔU_CA and q_AC = ΔU_BC
(D) q_BC = ΔH_AC and ΔH_CA > ΔU_CA

Answer 1

Answer: (B,C)
Solution:

 AC → Isochoric
AB →Isothermal
BC →Isobaric
# q_AC =  ΔU_BC = nC_V (T₂ – T₁)
W_AB = nRT₁ ln (V₂/V₁) A (wrong)
# q_BC = ΔH_AC = nC_P (T₂ – T₁)
W_BC = – P₂(V₁ – V₂)   B (correct)
# nC_P (T₁–T₂) < nC_V(T₁ – T₂) C (correct)
ΔH_CA < ΔU_CA
# D (wrong)