Question

If a gas expands at constant temperature, it indicates that:

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

Answer 1

Answer: (C)

kinetic energy of molecules remains same

If a gas expands at a constant temperature, it indicates that the kinetic energy of molecules remains the same.

The average kinetic energy of a gas molecule is given by the expression:

$\text{K.E}=\frac{3}{2}kT$

Thus, $\text{K.E}\propto T$

At constant temperature, kinetic energy is constant.