8.4 A plane electromagnetic wave travels in vacuum along the 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?
Hint: Recall the characterstics of electromagnetic wave.
Step 1: Find the direction of electric and magnetic field vectors.
As the electromagnetic wave is travelling in a vacuum along the z-direction, the electric field (E) and the magnetic field (H) are in the x-y plane and they are mutually perpendicular to each other.
Step 2: Find the wavelength.
Frequency of the wave,
Speed of light in vacuum, c = m/s
The wavelength of a wave is given by:
\(\lambda=\frac{c}{\nu} =\frac{3\times 10^{8}}{30\times 10^{6}}=10~m\)
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