Question

Air in a cylinder is suddenly compressed by a piston which is then maintained at the same position. As time passes, pressure of the gas

• A. Increases
• B. Decreases
• C. May increase or decrease depending on the nature of gas
• D. Remain the same

Answer 1

The correct option is B Decreases

We know that, ideal gas equation

$PV=nRT$

$\Rightarrow P=\frac{nRT}{V}$

$V=$ constant as piston is maintained at the same position.

$\therefore P\propto T$

But as time passes, heat from the system flows to the surrounding and hence temperature will decrease. So, pressure will also decrease.

Hence, option $\left(b\right)$ is correct.