In which of the following cases e.m.f. is induced?
(i) A current is started in a wire held near a loop of wire.
(ii) The current is switched off in a wire held near a loop of wire.
(iii) A magnet is moved through a loop of wire.
(iv) A loop of wire is held near a magnet.
An e.m.f. is induced in the following cases:
(i) When a current is started in a wire held near a loop of wire.
(ii) The current is switched off in a wire held near a loop of wire.
(iii) A magnet is moved through a loop of wire.
All these involve a change in magnetic flux, and hence an e.m.f. is induced.