Question

The $V-T$ graph shows some process for an ideal gas. The $INCORRECT$ statement is:

• A. In process $CD,$ pressure continuously increases.
• B. In process $EF,$ pressure continuously decreases.
• C. Pressure remains constant in all process $AB,CDandEF.$
• D. Internal energy of gas increases in all three processes.

Answer 1

Answer: (C)

For $A \rightarrow B:v \propto T$
$P$ is constant
For $C \rightarrow D:v=mT+C$
$\frac{nRT}{P}=mT+C$
$P=\frac{nRT}{mT + C}=\frac{nR}{\left(m + \frac{C}{T}\right)}$
$P$ increases, as $T$ increases.
For $E \rightarrow F:P=\frac{nRT}{mT - C}=\frac{nRT}{m - \frac{C}{T}}$
$P$ decreases, as $T$ increases.