A gas is filled in a cylinder fitted with a piston at a definite temperature and pressure. Explain on the basis of kinetic theory why on pulling the piston out, the pressure of decreases.

Explanation

On pulling the piston out, the volume of the cylinder for the given gas increase. The molecules of gas more space to move about. As a result, lesser number of molecules will collide with the walls of cylinder per second and hence less momentum is transferred to the walls per second. Further, these collisions take place on the larger area of the walls. Due to both these reasons, the pressure decreases.