Concepts Of Physics MCQ Edition [Volume 2]
- Exam
- Concepts Of Physics MCQ Edition [Volume 2]
- Subject
- Physics
- Chapter
- Laws of Thermodynamics
Concepts Of Physics MCQ Edition [Volume 2] · Physics · Laws of Thermodynamics
A gas is enclosed in a metallic cylinder fitted with a piston. The...
A gas is enclosed in a metallic cylinder fitted with a piston. The piston is abruptly moved inward to compress the gas and is held at this position. As time elapses, the pressure of the gas in the cylinder
Options
- Aincreases or decreases depending on the nature of the gas
- Bdecreases
- Cincreases
- Dremains constant
Correct answer
B. decreases
Step-by-step solution
When the gas is abruptly compressed, the process is approximately adiabatic. During this adiabatic compression, work is done on the gas, which increases its internal energy and consequently raises its temperature.
Since the cylinder is metallic, it acts as a good conductor of heat. As time elapses, the hot gas loses heat to the cooler surroundings through the conducting walls of the cylinder, causing its temperature to fall.
The piston is held at the compressed position, meaning the volume of the gas remains constant. According to the ideal gas law, at constant volume, the pressure of a given mass of gas is directly proportional to its absolute temperature ().
As the temperature of the gas decreases due to heat loss, its pressure also decreases.
Since the cylinder is metallic, it acts as a good conductor of heat. As time elapses, the hot gas loses heat to the cooler surroundings through the conducting walls of the cylinder, causing its temperature to fall.
The piston is held at the compressed position, meaning the volume of the gas remains constant. According to the ideal gas law, at constant volume, the pressure of a given mass of gas is directly proportional to its absolute temperature ().
As the temperature of the gas decreases due to heat loss, its pressure also decreases.