Write the causes of demagnetisation.

Explanation

**Step-by-Step Solution: Causes of Demagnetisation**

1. **Heating the Magnet**: One of the primary causes of demagnetisation is heating the magnet. When a magnet is heated, the thermal energy increases the movement of the atoms within the magnet, disrupting the alignment of the magnetic domains. As a result, the magnet loses its magnetism.

2. **Hammering the Magnet**: Another method to demagnetize a magnet is by hammering it. The mechanical shock from hammering causes the magnetic domains to become misaligned, leading to a loss of magnetism.

3. **Dropping from a Height**: Dropping a magnet from a height can also cause demagnetisation. The impact from the fall can disturb the arrangement of the magnetic domains, resulting in a weakened magnetic field.

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