Question

An electric fan becomes warm when continuously used for a long time. Why

Answer 1

This is because in electric fan electrical energy converts into mechanical energy. And it generates heat.

Answer 2

answer is due to heat produced by resistance
. All of the energy supplied to the fan is not entirely converted into mechanical energy due to resistance by the conductor ( wire) . Some of the energy is converted into heat energy as well. so the fan becomes hot after using for a long time