Question

A plane electromagnetic wave travels in vacuum along z-direction. What can you say about the directions of its electric and magnetic field vectors? If the frequency of the wave is 30 MHz, what is its wavelength?

Answer 1

The electromagnetic wave travels in a vacuum along the z-direction. The electric field (E) and the magnetic field (H) are in the x-y plane. They are mutually perpendicular.

Frequency of the wave, v = 30 MHz = 30 × 10⁶ s⁻¹

Speed of light in a vacuum, c = 3 × 10⁸ m/s

Wavelength of a wave is given as:

`lambda = "c"/"v"`

= `(3 xx 10^8)/(30 xx 10^6)`

= 10 m