Q 12-08-031JEE MainJEE Main 2026 (6 Apr, Shift 2)Easy
For an electromagnetic wave propagating through vacuum, $\vec{k}$, $\vec{E}$ and $\omega$ represent propagation vector, electric field and angular frequency, respectively. The magnetic field associated with this wave is represented by:
Answer: (B) $\dfrac{\vec{k} \times \vec{E}}{\omega}$
In an EM wave $\vec{E}$, $\vec{B}$ and $\vec{k}$ form a right-handed set with $\vec{E} \times \vec{B}$ along $\vec{k}$, so $\vec{B}$ is along $\vec{k} \times \vec{E}$.
Magnitude: $B = \dfrac{E}{c} = \dfrac{kE}{\omega}$ (since $c = \omega/k$). Hence $\vec{B} = \dfrac{\vec{k} \times \vec{E}}{\omega}$.
Solution by Sreeraj P, M.Sc Physics