Question

The amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is ${B_o} = 510nT$. What is the amplitude of the electric field part of the wave?

Answer 1

Electromagnetic waves are the waves that are produced when there is an interaction between electric and the magnetic field. They act in a perpendicular direction to each other.

Complete step by step answer:
Step I:
The amplitude of an electromagnetic wave is the height from the centerline to the top of the crest or the bottom of the trough. The amplitude of an electromagnetic wave is measured in meters.
Step II:
It is used to represent the energy carried by the electromagnetic waves. The energy carried by an electromagnetic wave is written as
$E = c{B_o}$---(i)
Where $E$is the energy of the wave
$c$is the speed of light in vacuum$= 3 \times {10^8}m/s$
${B_o}$is the amplitude of magnetic field of an electromagnetic wave in vacuum$= 510nT = 510 \times {10^{ - 9}}T$
Step III:
Substituting the values in equation (i) and solving,
$E = 3 \times {10^8} \times 510 \times {10^{ - 9}}$
$E = 153N{C^{ - 1}}$

$\therefore$ The amplitude of the electric field part of the wave is $153N{C^{ - 1}}$.

Note:
Also, there is a relation between the amplitude and energy of the wave.
$E \propto {A^2}$, Where $E$ is the energy and $A$ is the amplitude.
This relation shows that if the amplitude of the wave is doubled, then the energy of the electromagnetic wave is increased by four times.
Amplitude represents the energy carried by an electromagnetic wave. A wave that has a high value of amplitude, will have high energy and the wave which has a low amplitude will have low energy. It is to be noted that if a lot of energy is applied to the wave, only the amplitude changes. Other factors like length, wavelength, and frequency are unaffected.