Give scientific reasons.

The copper wire used in an electro-magnet is insulated.

The copper wire used in an electromagnet is insulated with an insulator like plastic in order to prevent the current from passing between the wire turns. If wire is not insulated than electricity will run across the wire turns and will not make loop after loop thus magnetic field will not be created.

If there is no insulation than too much current will be drawn due to less resistance to the flow of electricity.