To work with a tangent galvanometer, how do you set its coil?

Options

A. At an angle of `5 ^(@)` with magnetic meridian
B. Perpendicular to magnetic meridian
C. Along magnetic neridian
D. It does not require any setting

Answer

To set the coil of a tangent galvanometer, follow these steps:

### Step-by-Step Solution:

1. **Understand the Tangent Galvanometer**:
- A tangent galvanometer is an instrument used to measure the current by detecting the magnetic field produced by the current in its coil.

2. **Identify the Magnetic Meridian**:
- The magnetic meridian is the direction of the Earth's magnetic field at a given location. It runs from the geographic North to the geographic South.

3. **Position the Coil**:
- Set the plane of the coil of the tangent galvanometer to be **aligned with the magnetic meridian**. This means that the coil should be oriented such that it lies in the same plane as the magnetic field lines of the Earth.

4. **Ensure Perpendicularity**:
- The magnetic field produced by the current flowing through the coil should be **perpendicular to the plane of the coil**. This is crucial for accurate measurements.

5. **Check the Orientation**:
- Verify that the horizontal component of the Earth’s magnetic field is aligned in the north-south direction. The current flowing through the coil will generate a magnetic field in the east-west direction.

6. **Measure Current**:
- Once the coil is correctly set, you can pass a current through it and observe the deflection of the magnetic needle. The deflection angle (θ) can be used to calculate the current using the tangent law.