In a moving coil galvanometer , a radial magnetic field is produced due to the

Options

A. concave pole pieces of the magnet
B. rectangular coil
C. iron core
D. mirror

Answer

To answer the question "In a moving coil galvanometer, a radial magnetic field is produced due to the...", we can break down the explanation step by step.

### Step-by-Step Solution:

1. **Understanding the Structure of the Galvanometer**:
- A moving coil galvanometer consists of a coil suspended in a magnetic field. The coil is free to rotate about an axis.

2. **Role of Magnetic Field**:
- The magnetic field is crucial for the operation of the galvanometer. It interacts with the current flowing through the coil to produce a torque, which causes the coil to rotate.

3. **Radial Magnetic Field**:
- A radial magnetic field means that the magnetic field lines are directed radially inward or outward from a central point. This is essential for ensuring that the torque on the coil is maximized.

4. **Source of the Radial Magnetic Field**:
- The radial magnetic field in a moving coil galvanometer is produced by the **concave pole pieces** of the magnet. These specially shaped pole pieces create a magnetic field that is uniform and directed radially.

5. **Function of the Iron Core**:
- While the iron core is used in the galvanometer, its purpose is to enhance the magnetic field strength and increase the torque on the coil. However, it does not produce the radial magnetic field itself.

6. **Conclusion**:
- Therefore, the correct answer to the question is that the radial magnetic field in a moving coil galvanometer is produced due to the **concave pole pieces of the magnet**.

### Final Answer:
The radial magnetic field in a moving coil galvanometer is produced due to the **concave pole pieces of the magnet**.

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