Question

Which one is correct for a cyclic process as shown in the figure?

• A. $dU=0$
• B. $q=-w$
• C. $w=-314kJ$
• D. $q=3.14kJ$

Answer 1

Answer: (A), (B), (C)

The correct options are
A $dU=0$
B $q=-w$
C $w=-314kJ$

For a cyclic process, $dU=0$
and if, the process is clockwise work done is negative
$\therefore q=\Delta U-w\Rightarrow q=-w$
Also, $|w|=$ Area covered by sphere
$=\pi r^2=\pi \times [\frac{(V_2-V_1)}{2}{]}^2=\frac{\pi \times (20{)}^2}{2^2}=100\pi =100\times 3.14=314kJ$
As it is a clockwise cyclic process,
$w=-314kJ$