Question

Heat absorbed by a system in going through a cyclic process shown in figure is

• A. $10^{7}\pi J$
• B. $10^{6}\pi J$
• C. $10^{2}\pi J$
• D. $10^{4}\pi J$

Answer 1

Answer: (C)

We know that,
$\Delta u=0$ in cyclic process
So $\Delta Q=\Delta u-\Delta w$
$\Delta Q=-\Delta w$
We know,
work done = Area under P-V curve
= Area of circle
$=\frac{\pi r^{2}}{4}$
$=\frac{\pi }{4}\times \left(\right.30-10\left.\right)\times 10^{3}\left(\right.30-10\left.\right)\times 10^{- 3}$
$=\frac{\pi }{4}\times 20\times 20$
$=\frac{\pi }{4}\times 400$
$=100\pi $
$=10^{2}\pi \text{J}$
So Heat energy absorbed
$\Delta Q=-\Delta w$
$=10^{2}\pi J$