# Question #1906f

Aug 31, 2017

Similarities -

1) Both of them are entities of an electromagnetic field, hence electricity and magnetism are not separate subjects but are intimately related with one another.

2) A time varying electric field gives rise to a magnetic field whereas a time varying magnetic field generates an electric field. If on of them varies with time in space, the other one is induced.

3) Both of them are vector fields.

4) Both electric and magnetic fields exert forces on electric charges.

Major differences -

1) Electric field may have a non zero divergence. Thus they may have sources and sinks. However, the magnetic field is always solenoidal, no sources or sinks are possible.

2) In static cases (static charges and steady currents), Magnetic fields have non zero curl while electric fields have zero curl.

3) Electric fields exert velocity independent forces on electric charges while magnetic fields cause velocity dependent forces.

4) Electric fields can perform work on charges while magnetic fields exerting magnetic forces on charges can do no work on them.