Induced E-fields

Consider a bar magnet moving with velocity v in x-direction as seen from S. Does it produce electric field?

Let us look at the situation from S'. The magnet is at rest and we know, it produces only a magnetic field. You also know the magnetic field directions at different points due to this magnet. You can now do a field transformation from S' to S and get the fields in S. Indeed there is an electric field.

Any source that produces time varying B-field also produces E-field. Time varying B-field is always accompanied by E-field. Such an electric field is called Induced electric field.


If a conducting loop, coil or circuit is placed in an induced E-field, a current can be driven by the induced E-field. The emf is given by the Flux Rule.

The equations governing Induced E-field are:

∇ X E = -(∂ B /∂ t), ∇. E = 0.

These equations have the same mathematical structure as

∇ X B = μ₀ J and ∇. B = 0.

Hence induced E can be obtained from ∂ B/∂ t in the same way as B can be obtained from J .