Final answer:
An electric generator generates an electric current by rotating a coil in a magnetic field. This induces an electromotive force in the coil, which drives an alternating current.
Step-by-step explanation:
An electric generator generates an electric current by rotating a coil in a magnetic field. When the coil rotates, it cuts through the magnetic field lines, which induces an electromotive force (emf) in the coil. This emf drives an alternating current (AC) through the coil, which can be used to power electrical devices.