A gas is contained in a metallic cylinder fitted with a piston. The piston is suddenly moved in to compress the gas and is maintained at this position. As time passes the pressure of the gas in the cylinder.
1. When the piston is moved to compress the gas, the volume of the gas reduces and pressure and temperature increases.
2. After that piston is maintained at this position. So, volume becomes constant.
3. But during this sudden compression heat is generated. And since the cylinder is metallic this heat can escape out of the cylinder as metals are good conductors of heat.
4. When heat escapes out of the cylinder, the temperature of the gas will decrease which will, in turn, decrease the pressure of the gas.