An ideal monoatomic gas is carried along the cycle $A B C D A$ as shown in the figure. The total heat…

An ideal monoatomic gas is carried along the cycle $A B C D A$ as shown in the figure. The total heat absorbed during this process is
  1. $10.5 p_0 V_0$
  2. $7.5 p_0 V_0$
  3. $2.5 p_0 V_0$
  4. $1.5 p_0 V_0$

Solution

Heat absorbed means heat is extracted from source, i.e.Q must be positive. This occurs along path $ \begin{aligned} \quad A \rightarrow B \rightarrow C . & \\ \therefore & \text { Heat added }=\Delta Q_{A B C}=\Delta U_{A B C}+\Delta W_{A B C} \\ = & n C_V\left(T_C-T_A\right)+3 p_0\left(2 V_0-V_0\right) \\ = & n \frac{3}{2} R\left(T_C-T_A\right)+3 p_0 V_0=\frac{3}{2}\left(n R T_C-n R T_A\right)+3 p_0 V_0 \\ = & \frac{3}{2}\left(p_C V_C-p_A V_A\right)+3 p_0 V_0 \\ = & \frac{3}{2}\left(3 p_0 2 V_0-p_0 V_0\right)+3 p_0 V_0 \\ = & \frac{3}{2} \times 5 p_0 V_0+3 p_0 V_0=\frac{21}{2} p_0 V_0=10.5 p_0 V_0 \end{aligned} $

Asked in: AP EAMCET 2018 (24 Apr Shift 1)

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