A radio wave has a maximum magnetic field of \( 10^{-4}\,\mathrm{T} \) on arrival at a receiving antenna. The maximum electric field intensity of the wave is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \( 3\times10^{4}\,\mathrm{V/m} \)
In an electromagnetic wave, the two field amplitudes are related through the speed of light as \( E_0=cB_0 \). Here \( c=3\times10^{8}\,\mathrm{m\,s^{-1}} \).
\( \begin{aligned} E_0 &= cB_0 \\ &= 3\times10^{8}\,\mathrm{m\,s^{-1}}\times10^{-4}\,\mathrm{T} \\ &= 3\times10^{4}\,\mathrm{V/m} \end{aligned} \)
NCERT (2026-27):
Nature of Electromagnetic Waves – “… It is also seen from Maxwell’s equations that the magnitude of the electric and the magnetic fields in an electromagnetic wave are related as
\( B_0=(E_0/c) \)\( \qquad (8.10) \)”