Question

A fixed thermally conducting cylinder has a radius $R$ and height $L_0$. The cylinder is open at its bottom and has a small hole at its top. A piston of mass $M$ is held at a distance $L$ from the top surface as shown in Fig. The atmospheric pressure is $p_0$.
The piston is now pulled out slowly and held at a distance $2L$ from the top. The pressure in the cylinder between its top and the piston will then be:

• A. $P_0$
• B. $\frac{P_0}{2}$
• C. $\frac{P_0}{2}-\frac{Mg}{\pi R^2}$
• D. $P_0-\frac{Mg}{\pi R^2}$

Answer 1

The correct option is A $P_0$

Since the cylinder has a hole at its top, it is open to atmosphere. So pressure in the cylinder between its top and the piston will then be = atmospheric pressure $=P_o$, Hence the correct choice is 'A'.