The restoring couple in the moving coil galvanometer is due to

Options

A. Current in the coil
B. Mangetic field of the magnet
C. Material of the coil
D. Twist produced in the suspension wire

Answer

To solve the question regarding the restoring couple in a moving coil galvanometer, we can break down the explanation into clear steps:

### 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 typically mounted on a pivot and can rotate freely.

2. **Role of the Magnetic Field**:
- When an electric current passes through the coil, it experiences a torque due to the interaction with the magnetic field. This torque causes the coil to rotate.

3. **Restoring Couple Explained**:
- As the coil rotates, it is subject to a restoring couple that opposes this rotation. This couple is essential for bringing the coil back to its original position when the current is removed.

4. **Source of the Restoring Couple**:
- The restoring couple in the galvanometer is primarily due to the twist in the suspension wire (or spring) that holds the coil. When the coil rotates, the suspension wire twists, creating a torque that acts in the opposite direction to the coil's rotation.

5. **Conclusion**:
- Therefore, the restoring couple in the moving coil galvanometer is due to the twist produced in the suspension wire.

### Final Answer:
The restoring couple in the moving coil galvanometer is due to the twist produced in the suspension wire.

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