The ratio of amplitude of magnetic field to the amplitude of electric field for an electromagnetic wave propagating in vacuum is equal to
-
the speed of light in vacuum
-
the reciprocal of the speed of light in vacuum
-
the ratio of magnetic permeability to the electric susceptibility of vacuum
-
unity
B.
the reciprocal of the speed of light in vacuum
as E=cB
so the required ratio
Therefore, the ratio of the amplitude of magnetic field to the amplitude of electric field for an electromagnetic wave propagating in a vacuum is equal to the reciprocal of the speed of light.