Question

For a gas at a particular temperature on an average, the quantity which remains same for all molecules is

• A. velocity
• B. momentum
• C. kinetic energy
• D. angular momentum

Hint:

In kinetic theory: \[ \bar{K}\propto T \] Average kinetic energy is the quantity directly linked with temperature.

Answer 1

The Correct Option is C

Concept:
In kinetic theory, molecules have different velocities and momenta at any instant. At a given temperature, the average translational kinetic energy depends only on temperature: \[ \bar{K}=\frac{3}{2}kT \] ip

Step 1: Identify what depends only on temperature.
The average kinetic energy of gas molecules is fixed by temperature alone. ip

Step 2: Eliminate the other quantities.
Velocity, momentum, and angular momentum are not the same for all molecules. ip Hence, the correct answer is:
\[ \boxed{(C)\ \text{kinetic energy}} \]