If L be the length of a bar magnet then separation between the two poles is naarly

Options

A. `0/10 L `
B. `6/7 L `
C. `1/3L `
D. `1/2 L `

Answer

To determine the separation between the two poles of a bar magnet when given its length \( L \), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definitions**:
- The **geometrical length** of the bar magnet is the total length of the magnet, denoted as \( L \).
- The **magnetic length** is the effective distance between the north and south poles of the magnet.

2. **Relate Geometrical Length to Magnetic Length**:
- It is known that the magnetic length is approximately \( 0.83 \) to \( 0.85 \) times the geometrical length of the bar magnet.
- Therefore, we can express the magnetic length \( L_m \) as:
\[ L_m \approx 0.83 \times L \quad \text{or} \quad L_m \approx 0.85 \times L \]

3. **Calculate the Magnetic Length**:
- For practical purposes, we can take an average value for the magnetic length. Using \( 0.85 \) as a common approximation, we have:
\[ L_m \approx 0.85L \]

4. **Determine the Separation**:
- The separation between the two poles of the bar magnet is therefore approximately:
\[ \text{Separation} \approx 0.85L \]

5. **Final Answer**:
- Thus, the separation between the two poles of the bar magnet is nearly equal to \( \frac{6}{7}L \) since \( 0.85 \) can be approximated as \( \frac{6}{7} \).

### Conclusion:
The separation between the two poles of a bar magnet of length \( L \) is approximately \( \frac{6}{7}L \).

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