2. Figure 1 shows a reversible cycle through which 0.2 mol of a monatomic ideal gas is taken. Volume V_d = 4.0V_a, V_b = V_a, and V_c = V_d. Process bc is an isothermal expansion, with p_b = 10.0 atm (=1.013×10⁶ Pa) and V_b = 1.0 × 10⁻³ m³. Process da is adiabatic (pVᵞ = constant with γ = C_p/C_V) with p_a = 5.0 atm. For the cycle, find (a) the temperature at point a, T_a: (3)______, (b) the energy added to the gas as heat, (4)______ (c) the efficiency of the cycle, (5)______, and (d) the entropy change ΔS during process bc, (6)______.