Nature of EM Waves & Wave Equation question from JEE Main 2019 (8 Apr, Shift 1)

Answer: (c)

1. In an EM wave $B = \dfrac{E}{c}$ and $\vec E \times \vec B$ points along the direction of travel.
2. $B = \dfrac{6}{3\times10^{8}} = 2\times10^{-8}\text{ T}$
3. Travel along $+x$ with $\vec E$ along $y$: $\hat y \times \hat z = \hat x$, so $\vec B$ is along $z$.
4. So the answer is (c) $2\times10^{-8}$ T along z-direction.