Question

According to the kinetic theory of gases, the absolute temperature of a gas is directly proportional to

• A. Average kinetic energy of molecules
• B. Average velocity of molecules
• C. Average potential energy of molecules
• D. Volume of the gas

Hint:

Remember that in the context of the kinetic theory, temperature is fundamentally related to the kinetic energy of particles rather than their velocity or potential energy.

Answer 1

The Correct Option is A

Step 1: Recall the main idea.
The kinetic theory of gases links the temperature of a gas to the motion of its tiny particles. We must find what the absolute temperature is directly proportional to.
Step 2: Write the key relation.
The theory says the average kinetic energy of one molecule is given by\[ \overline{E_k} = \frac{3}{2} k_B T \]where $T$ is the absolute temperature and $k_B$ is a constant.
Step 3: Read the proportion.
Since $\frac{3}{2} k_B$ is a fixed number, this means $\overline{E_k} \propto T$. So the average kinetic energy goes up in step with temperature.
Step 4: Check average velocity.
Velocity is not directly proportional to $T$. In fact speed grows with the square root of $T$, so it is not a simple direct link.
Step 5: Check the other choices.
In an ideal gas the particles have almost no potential energy, so that does not link to $T$. Volume only links to $T$ at fixed pressure, which is a special case, not a general rule.
Step 6: Final choice.
The clean direct link is with average kinetic energy.\[ \boxed{\text{Average kinetic energy of molecules}} \]