Question 71: Thermodynamics & KTG

Question

An ideal gas is taken through the cycle A $$	o$$ B $$	o$$ C $$	o$$ A, as shown in the figure. If the net heat supplied to the gas in the cycle is 5 J, the work done by the gas in the process 
C $$	o$$ A is,

Accepted Answer

Net work done by a gas,
$$\begin{array}{ll}
\Delta W_{A B}=p \cdot \Delta V=10 	imes(2-1)=10 \mathrm{~J} \
\Delta W_{B C}=0 & 	ext { (as } V=	ext { constant) }
\end{array}$$
From first law of thermodynamics, we have,
$$\begin{aligned}\Delta Q & =\Delta W+\Delta U \
\Delta U & =0
\end{aligned}$$
(process $$A B C A$$ is cyclic)
Therefore, $$\Delta Q=\Delta W_{A B}+\Delta W_{B C}+\Delta W_{C A}$$
$$\begin{aligned}
	herefore \quad \Delta W_{C A} & =\left(\Delta Q-W_{A B}-W_{B C}ight) \
& =(5-10-0) \mathrm{J}=-5 \mathrm{~J}
\end{aligned}$$

Answer

$$-5$$ J

Answer

$$-10$$ J

Answer

$$-15$$ J

Answer

$$-20$$ J

Thermodynamics & KTG

An ideal gas is taken through the cycle A $\to B \to C \to A, as shown in the figure. If the net heat supplied to the gas in the cycle is 5 J, the work done by the gas in the process C \to$ A is,

Choose the correct answer: