What's the meaning of amplitude in EM wave?

In summary, the amplitude of an electromagnetic wave is the varying electric field and magnetic field. In classical terms, the square of the amplitude is proportional to the energy density, but it does not have its own meaning. In water waves, the amplitude represents the magnitude of variation of water molecules. Similarly, in an EM wave, the amplitude represents the magnitude of the E-field vector and defines the polarization of the wave.
  • #1
particle
3
0
i learned that EM wave is varying electric field and magnetic field .But what's the meaning of the amplitude of EM wave? The displacement of the photon or the magnitude of the electric/magnetic field(no. of photons)?
 
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  • #2
Classically, the square of the amplitude of a wave is proportional to the energy [density].
 
  • #3


but it doesn't have its own meaning?
in water wave, the amplitude is the magnitude of the variation of water molecular.
then what's varying in the EM wave?
 
  • #4
particle said:
but it doesn't have its own meaning?
in water wave, the amplitude is the magnitude of the variation of water molecular.
then what's varying in the EM wave?

In the simplest form, it's the amplitude of the E-field vector. This is what typically defines the polarization of an EM wave.

Zz.
 

1. What is amplitude in an electromagnetic (EM) wave?

Amplitude refers to the maximum displacement of the electric and magnetic fields in an EM wave. It is a measure of the strength or intensity of the wave.

2. How does amplitude affect the energy of an EM wave?

The energy of an EM wave is directly proportional to its amplitude. This means that the higher the amplitude, the more energy the wave carries.

3. Can amplitude change during the propagation of an EM wave?

Yes, the amplitude of an EM wave can change as it propagates through a medium. This can happen due to factors such as absorption, reflection, and diffraction.

4. How is amplitude related to the loudness of an EM wave?

In the context of sound, loudness is a measure of the perceived intensity of a wave. Amplitude is directly related to loudness, as a higher amplitude will result in a louder sound.

5. What is the unit of measurement for amplitude in EM waves?

The SI unit for amplitude is meters (m). However, in the context of EM waves, amplitude is often measured in terms of electric field strength (V/m) or magnetic field strength (A/m).

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