Question

Ratio of average kinetic energies of equal masses of \(H_2\) and \(He\) at the same temperature is

• A. \(2:1\)
• B. \(1:2\)
• C. \(1:1\)
• D. \(4:1\)

Hint:

For all gases at the same temperature: \[ \text{Average kinetic energy is the same} \] This is a direct consequence of the kinetic theory of gases.

Answer 1

The Correct Option is C

Step 1: The average kinetic energy of gas molecules is given by: \[ \text{Average K.E.} = \frac{3}{2}kT \]
Step 2: The above expression shows that average kinetic energy depends only on temperature and not on:
Nature of the gas
Molecular mass of the gas
Amount of the gas
Step 3: Since both \(H_2\) and \(He\) are at the same temperature, their average kinetic energies are equal. \[ \Rightarrow \text{Ratio} = 1:1 \]