Reversible expansion of an ideal gas under isothermal and adiabatic conditions are as shown in the figure. A B Isothermal expansion A C Adiabatic expansion Which of the following option is not correct?

Step-by-step solution

From first law of thermodynamics, U = q + W In adiabatic expansion, q=0 U = W During expansion of a gas w is negative i.e w < 0 or U < 0 . We know that, U = nC _ V T array lclc & nC _ V T < 0 & or & T < 0 & T _ C - T _ A < 0 & or & T _ C < T _ A array Thus, option (4) is incorrect while the remaining options are correct.