Q 12-08-186JEE MainJEE Main 2020 (2 Sep, Shift 2)Easy
In a plane electromagnetic wave, the directions of electric field and magnetic field are represented by $\hat k$ and $2\hat i - 2\hat j$, respectively. What is the unit vector along direction of propagation of the wave?
Answer: (A) $\dfrac{1}{\sqrt2}(\hat i + \hat j)$
The wave travels along $\vec E \times \vec B$:
$$\hat k \times (2\hat i - 2\hat j) = 2\hat j + 2\hat i$$
Unit vector: $\dfrac{1}{\sqrt2}(\hat i + \hat j)$.
Solution by Sreeraj P, M.Sc Physics