OnlineCBT
Physics · PYQ NEET UG 2021
हिन्दीFor a plane electromagnetic wave propagating in x-direction, which one of the following combination gives the correct possible directions for electric field (E) and magnetic field (B) respectively?
Correct answer · Option 3
\( -\hat{j} + \hat{k}, -\hat{j} - \hat{k} \)
Explanation
For an electromagnetic wave propagating along \( \hat{i} \), \( \vec{E} \) and \( \vec{B} \) must be perpendicular to each other and to \( \hat{i}\, i.e., \vec{E} \cdot \vec{B} = 0 \). Testing the dot products, option (3) gives \( (-\hat{j} + \hat{k}) \cdot (-\hat{j} - \hat{k}) = 1 - 1 = 0 \).
