Question

how alternative current is he different from direct current DC

Answer 1

Direct current flows in only one direction. It cannot be used for large scale industries and household purposes. It is non oscillatory. It can change in magnitude but direction remains the same.

A current that changes in magnitude and direction after equal intervals of time is called Alternating Current.  It reverses its direction periodically with time. Thus it is oscillatory. It is used widely in household appliances like iron, refrigerator etc.

Answer 2

AC generator is an alternative current changes it's direction in every half rotation while,in DC generator current always flows in one direction.

eg:- power station for AC and electric motor for DC.