An electromagnetic wave is propagating in a non-magnetic dielectric medium ( _r = 1 ). The amplitudes of the oscillating electric and magnetic fields in this medium are 60 V m ⁻¹ and 4 10⁻⁷ T respectively. The relative permittivity of the medium is (Speed of light in vacuum c = 3 10^8 m s ⁻¹ )

Step-by-step solution

The speed of the electromagnetic wave in the medium is given by the ratio of the amplitudes of the electric and magnetic fields: v = E₀ B₀ = 60 4 10⁻⁷ = 1.5 10^8 m s ⁻¹ The speed of the wave in a medium is also given by: v = c _r _r Squaring both sides and rearranging for relative permittivity _r : _r = c^2 v^2 _r Given that the medium is non-magnetic, _r = 1.0 . Substituting the values: _r = ( 3 10^8 1.5 10^8 )^2 1 1.0 = (2)^2 = 4.0 Answer: 4.0