Direction of magnetic field at equatorial point

Options

A. parallel to M
B. perpendicular to M
C. making an angle of`45^@` with M
D. antiparallel to M

Answer

To determine the direction of the magnetic field at the equatorial point of a bar magnet, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Bar Magnet**:
- A bar magnet has two poles: a North pole (N) and a South pole (S). The magnetic field lines emerge from the North pole and enter the South pole.

2. **Identifying the Equatorial Point**:
- The equatorial point is located at a position that is equidistant from both the North and South poles of the magnet.

3. **Direction of Magnetic Field**:
- At the equatorial point, the magnetic field due to the North pole (B_N) and the South pole (B_S) will be in opposite directions.
- The magnetic field lines are directed from the North pole to the South pole outside the magnet.

4. **Calculating the Resultant Magnetic Field**:
- The magnetic field at the equatorial point is the vector sum of the fields due to both poles. Since these fields are equal in magnitude but opposite in direction at the equatorial point, they will cancel each other out.
- However, the direction of the magnetic field at the equatorial point is still influenced by the orientation of the magnet.

5. **Conclusion**:
- The direction of the magnetic field at the equatorial point is parallel to the magnetic axis of the magnet, which is the line that connects the North and South poles.
- Therefore, the magnetic field at the equatorial point is directed from the North pole to the South pole, which is parallel to the magnetic moment vector (M) of the magnet.

### Final Answer:
The direction of the magnetic field at the equatorial point is **parallel to the magnetic moment vector (M)**.

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