Question

How are electric and magnetic fields related?

Answer 1

E=c*B

Explanation:

a simple relation to relate electric and magnetic field in an electromagnetic field is by using a simple relation of E=cB
where c is the speed of light because electromagnetic wave travels by speed c.
you can obtain this relation by using fact that product of permittivity of free space and permeability is 1/c2 .
now further complex relations involving transformation of fields with changing of frames can be obtained in special relativity by using lorentz transformations .

Answer 2

more explanation

Explanation:

permeability : measure of extent to which magnetic field can penetrate matter

here the whole quantity outside the integral multiplied by `4pi` is called permeability of free space and has a value of `10^-7` `NA^-2` .
Every medium has different permeability .

permittivity : ability of electric field to affect and get affected by the medium or the ability of medium to polarize in electric field and hence reduce it

permittivity of free space has value of `8.854 * 10^-12` `C^2N^-1m^-2` .
each medium has different permittivity