Final answer:
An electric generator converts mechanical work into electric energy through electromagnetic induction, which involves rotating a coil within a magnetic field. It is not limited to operating in an open circuit nor solely responsible for the coil in an electric motor.
Step-by-step explanation:
An electric generator is a device that converts mechanical work into electric energy. It operates on the principle of electromagnetic induction which involves inducing an electromotive force (emf) by rotating a coil within a magnetic field. The key function of a generator is not to operate only when a circuit is open or to be responsible solely for the coil that turns inside an electric motor; rather, it uses electromagnetic induction to produce the emf. Electric generators and motors share similar constructions, but while generators convert mechanical energy to electrical energy, motors do the opposite.