Do electromagnetic waves fade with distance in vacuum?

In summary, electromagnetic waves do not fade with distance in a vacuum; they propagate indefinitely without losing energy. However, their intensity diminishes as the wavefront spreads out over larger areas, resulting in a decrease in observed signal strength. This phenomenon is described by the inverse square law, which states that the intensity of the wave is inversely proportional to the square of the distance from the source.
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yashraj
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Do electromagnetic wave gets weaker with the increasing distance from the source in its travel ?
I want to know that when a charged particle accelerates then the electromagnetic wave so produced will loose it's strength or can say fades with distance or not ? If yes then what happens to its frequency and also tell me if electromagnetic waves fades away with increasing distance from the source then how physicists detects signals from the outer space which have travelled thousands of light years ?
 
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Welcome to PF.

As an EM wave radiates out into space, the energy is distributed over the surface of a radially growing sphere. That causes the EM wave energy density to be reduced by the inverse square law.

The frequency of the EM wave remains the same.

The signals detected from space start out with incredible energy. After the inverse square law has been applied, there is sufficient energy remaining, to enter the aperture of the telescope, and for the signals to be detected.
 
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  • #3
Baluncore said:
Welcome to PF.

As an EM wave radiates out into space, the energy is distributed over the surface of a radially growing sphere. That causes the EM wave to be reduced by the inverse square law.

The frequency of the EM wave remains the same.

The signals detected from space start out with incredible energy. After the inverse square law has been applied, there is sufficient energy remaining, to enter the aperture of the telescope, and for the signals to be detected.
Thank you for the answer. I was actually thinking almost same but I wanted to make sure that I was right.
 
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