Which of the following devices works on the principle of electromagnetic induction?
Generator
Ammeter, Voltmeter, and Galvanometer work on the principle of the magnetic field around the current carrying conductor. A current carrying wire produces a magnetic field around it and due to the magnetic field in the vicinity the magnetic needle of the compass experiences a torque in this field, so it deflects to align itself in the direction of the magnetic field.
The generator works on the principle of electromagnetic induction i.e. production of e.m.f in a conductor under a varying magnetic field. Whenever there is a change in magnetic flux linked with a coil, an emf is induced, which then produces an induced current. The magnitude of the induced emf is directly proportional to the rate of change of magnetic flux linked with the coil.