A quasi-static cycle of a monoatomic ideal gas contains an isothermal process (ab), followed by an isochoric process (bc) and an adiabatic process (ca) as shown in the figure. The volumes of the gas are V₁ and V₂ at a and b, respectively. If the cycle has heat input Qin and output Qout, then the efficiency of the cycle is defined as η = (Qin − Qout)/Qin. The correct statement(s) is/are: [Given: ln 2 ≈ 0.7]