Question

A plane EM wave is travelling in vaccum along X- direction. What can you say about the directions of magnetic and electric fields? If the frequency of the wave is $30MHz$, what is its wavelength?

Answer 1

It electric field and magnetic field will be along Y axis and Z axis. However its more accurate to say both vectors will be in Y-Z plane and perpendicular to each other.

$\nu =\frac{c}{\lambda }$

or, $\lambda =\frac{c}{\nu }$

$=\frac{3\times {10}^8}{30\times {10}^6}$

$=10m$