The number of translational degree of freedom for a diatomic gas is

Options

A. 2
B. 3
C. 5
D. 6

Answer

To determine the number of translational degrees of freedom for a diatomic gas, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Degrees of Freedom**:
- Degrees of freedom refer to the number of independent ways in which a system can move. For gases, these are categorized into translational, rotational, and vibrational movements.

2. **Translational Degrees of Freedom**:
- Translational degrees of freedom correspond to the movement of the gas molecules in three-dimensional space.
- A molecule can move along the x-axis, y-axis, and z-axis. Therefore, there are **3 translational degrees of freedom**.

3. **Rotational Degrees of Freedom**:
- Diatomic gases can also rotate. A diatomic molecule can rotate about two axes perpendicular to the line joining the two atoms.
- Thus, there are **2 rotational degrees of freedom** for a diatomic gas.

4. **Total Degrees of Freedom**:
- While the question specifically asks for translational degrees of freedom, it’s useful to note that the total degrees of freedom for a diatomic gas would be the sum of translational and rotational degrees of freedom.
- Total = Translational (3) + Rotational (2) = 5.

5. **Final Answer**:
- The number of translational degrees of freedom for a diatomic gas is **3**.