A very small magnet is placed in the magnetic meridian with its S-pole pointing north. The null point is obtained 20 cm away from the centre of the magnet. What is the magnetic moment of the magnet if earth's field is `0.3xx 10^(-4) T`?

Explanation

To find the magnetic moment of the magnet, we can follow these steps:

### Step 1: Understand the setup
A small magnet is placed in the magnetic meridian with its south pole pointing north. The null point is observed 20 cm away from the center of the magnet. The Earth's magnetic field (Bh) is given as \(0.3 \times 10^{-4} \, T\).

### Step 2: Identify the relationship at the null point
At the null point, the magnetic field due to the magnet (B) and the horizontal component of the Earth's magnetic field (Bh) are equal in magnitude but opposite in direction. Therefore, we can write:
\[
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