Working of AC electric generator :
1) The coil is at rest in vertical position with side (A) of coil at top position and side (B) at bottom position no current will be induced in it.
2) When the coil is rotated in clockwise direction current will be induced in it and it flows from A to B.
3) If we continue the rotation of coil once again current becomes zero.
4) The coil comes to vertical position with B side at top A at bottom position.
5) During second part of the rotation current generated follows the same pattern except that the direction of current is reversed.
6) Thus the current produced is AC current.