Question

An emf is produced in a coil, which is not connected to an external voltage source. This can be due to
(b) the coil moving in a time varying magnetic field
(c) the coil moving in a constant magnetic field
(d) the coil is stationary in external spatially varying magnetic field, which does not change with time.

Answer 1

An emf is produced in a coil without connecting it to an external voltage source only when amount of magnetic flux linked with the coil is charging with time. When the coil is entering or leaving the constant magnetic field partially, an emf may be produced in the coil.
Hence the correct option is a, b and c
HOPE THISS HELFUL