Question

A plane electromagnetic wave propagates along the $+x$ direction in free space. The components of the electric field $\vec{E}$ and magnetic field $\vec{B}$ vectors associated with the wave in Cartesian frame are:

• A. $E_x, B_x$
• B. $E_y, B_z$
• C. $E_z, B_y$
• D. $E_x, B_y$

Hint:

In electromagnetic waves, the electric field, magnetic field, and direction of propagation are always mutually perpendicular to each other.

Answer 1

The Correct Option is B

For a plane electromagnetic wave propagating along the $+x$ direction, the electric field $\vec{E}$ and magnetic field $\vec{B}$ are perpendicular to each other and to the direction of propagation. The direction of propagation is along the $x$-axis, so the electric field is along the $y$-axis and the magnetic field is along the $z$-axis. Hence, the correct components of the electric and magnetic fields are $E_y$ and $B_z$, respectively.
Therefore, the correct answer is $\boxed{E_y, B_z}$.