Question

The following are the $P-V$ diagrams for cyclic processes for a gas. In which of these processes is heat absorbed by the gas ?

• A. $\left(\right.i\left.\right),\left(\right.iii\left.\right)$
• B. $\left(\right.ii\left.\right),\left(\right.iii\left.\right)$
• C. $\left(\right.iii\left.\right),\left(\right.iv\left.\right)$
• D. $\left(\right.i\left.\right),\left(\right.ii\left.\right),\left(\right.iii\left.\right)$

Answer 1

Answer: (D)

(i) Clockwise cycle on $P-V$ diagram
$\Delta W_{cyclic}=+ve=\Delta Q_{cyclic}$
Heat is absorbed
(ii) anticlockwise cycle on $V-P$ diagram
$\Delta W_{cyclic}=+ve=\Delta Q_{cyclic}$
heat is absorbed
(iii) clockwise cycle on $P-V$ diagram
$\Delta W_{cyclic}=+ve=\Delta Q_{cyclic}$
heat is absorbed
(iv) clockwise cycle on $V-P$ diagram
$\Delta W_{cyclic}=-ve=\Delta Q_{cyclic}$
heat is rejected