on the basis of domain theory
A. 1. In a ferro magnetic substance, large no. of domains occur.
2. The direction of magnetisation with in a domain is different from that in the neighbouring domains.
3. The boundary lines are indicate the domains and the arrow within domain indicates total magnetisation.
4. From fig, that the arrows with in the domain point along different directions.
5. As a result, the net magnetisation of the specimen as a whole is almost zero.