Question

What is the formula for galvanometer?

Answer 1

The formula for a galvanometer, which is an instrument used to measure small electric currents, is based on the relationship between the deflection of the needle (or the pointer) and the current passing through it.

For a moving coil galvanometer, the key relationship is given by:

\[
\theta = \frac{I}{K}
\]

Where:
- \(\theta\) is the deflection of the needle (in radians or degrees).
- \(I\) is the current flowing through the galvanometer.
- \(K\) is a constant, known as the galvanometer's "sensitivity constant," which depends on the physical properties of the galvanometer (like the number of turns in the coil, the strength of the magnetic field, etc.).

### Additional Details:
- If you want to find the current \(I\) based on the deflection \(\theta\), the formula is rearranged as:

\[
I = K \cdot \theta
\]

- The sensitivity constant \(K\) can also be written as:

\[
K = \frac{B \cdot A \cdot N}{\phi}
\]

Where:
- \(B\) is the magnetic field strength.
- \(A\) is the area of the coil.
- \(N\) is the number of turns in the coil.
- \(\phi\) is the torque constant, related to the restoring force of the spring that controls the deflection.

This formula helps describe how the galvanometer works and how it reacts to the applied current.