In a plane electromagnetic wave, the magnetic field oscillates sinusoidally at a frequency of \( 2.0\times10^{10}\,\mathrm{Hz} \) and amplitude \( 1.6\times10^{-7}\,\mathrm{T} \). The amplitude of the oscillating electric field is:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → \( 48\,\mathrm{V\,m^{-1}} \)
In an electromagnetic wave in vacuum the amplitudes of the electric and magnetic fields are related by the speed of light: \( E_0 = cB_0 \). The frequency is not needed for this.
\( E_0 = (3\times10^{8}\,\mathrm{m\,s^{-1}})(1.6\times10^{-7}\,\mathrm{T}) \)
\( E_0 = 48\,\mathrm{V\,m^{-1}} \)