Question

If a gas is expanded at constant temperature, then which of the following is/are correct?

• A. The pressure of gas decreases
• B. The kinetic energy of the gas moleules remains the same
• C. The kinetic energy of the gas molecules decreases
• D. The number of molecules of the gas increases

Answer 1

Answer: (A), (B)

The kinetic energy of the gas moleules remains the same

At constant temperature when gas expands the K.E. of the moleucles remains the same, but the pressure decreases (Boyle's law). $(\because P\propto \frac{1}{V}\text{at constant T}\text{and}K.E(permole)=\frac{3}{2}nRT)$