Given: Frequency of electromagnetic wave f = 2.0×10¹⁰ Hz

Amplitude of the electromagnetic wave i.e. E₀ = 48 V m^–1

(a) Wavelength of the electromagnetic wave can be calculated as follows:

v = c / λ

also, λ = c/v

where c is the speed of light in vacuum

v is the frequency of electromagnetic wave

and λ is the wavelength of electromagnetic wave

Substituting the values

On calculating, we get

⇒ λ = 0.015 m

(b) Amplitude of the electromagnetic wave i.e. E₀ = 48 V m^–1

Amplitude of the oscillating magnetic field is given by the following expression:

B₀ = E₀/c

On calculating we get:

⇒ B₀ = 1.6 × 10^-7 Tesla

(c) The average energy density of the E field equals the average energy density of the B field can be proved as follows:

The energy density of electric field (i)

Where is the permittivity of free space

The energy density of magnetic field is given as follows:

_{......................}(ii)

Where is the permeability of free space

The relation between Electric field and magnetic field i.e. E and B is as follows:

On squaring both the sides, we get following relation

Or,

From equation (i) and (ii), we get

∴ U_E = U_B