Question

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. What happens to the pressure of the gas in the cylinder as time passes?
A. Increases
B. Decreases
C. Remains constant
D. Increases or decreases depending on the nature of the gas.

Answer 1

Hint: Before we go to solve this question let’s think about the relationship between temperature and pressure and how it is related to one another. We can say that as the temperature decreases the pressure will also decrease and vice-versa. Hence these two are directly proportional to each other by considering the ideal gas equation.

Complete step by step solution:
When the gas gets compressed, the volume will decrease. Since the volume is decreased, we can say that the pressure and temperature will increase. When the temperature of the gas has been increased, as time passes the cylinder will radiate heat to the surroundings thereby decreasing the temperature.

When the piston is maintained at that position after the compression that means the volume is constant. From the ideal gas equation, we can conclude that if the temperature is decreasing and the volume is constant therefore pressure will also decrease.

Hence, option B is the correct answer

Note:suppose instead of a metallic cylinder if we consider a cylinder that is made of an insulating material, the heat loss from the system after the compression becomes zero. Hence, the pressure within the system will be constant.