According to the general formulae for electric and magnetic fields for em waves \( E_x = E_0\sin(kz - \omega t) \) and \( B_y = B_0\sin(kz - \omega t) \); what will be the value of \( B_0 \) if \( E_0 = 6.3\,\mathrm{V/m} \).
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \( 2.1 \times 10^{-8}\,\mathrm{T} \)
In an electromagnetic wave the amplitudes of the electric and magnetic fields are related through the speed of light: \( E_0 = c\,B_0 \).
\( \displaystyle B_0 = \frac{E_0}{c} = \frac{6.3\,\mathrm{V\,m^{-1}}}{3\times10^{8}\,\mathrm{m\,s^{-1}}} = 2.1\times10^{-8}\,\mathrm{T} \)
Note: This question is from NCERT (2026-27). NTA sets numerical questions from NCERT too, so do not ignore NCERT while practising numericals.
NCERT (2026-27):
Nature of Electromagnetic Waves – …
