Electromagnetic wave emission after source vanishes

In summary, electromagnetic waves have a self-sustaining nature where a disturbance in the electric field, created by a charge accelerating and then stopping, propagates infinitely outward. Even if the source charge disappears, the changing electric and magnetic fields will continue to sustain each other and emit waves forever. This is similar to throwing a pebble into a pond, where the initial waves continue to radiate outwards even after the pebble has stopped creating new ones.
  • #1
PeteyCoco
38
1
I'm reading about electromagnetic waves and I can't make sense of their self-sustaining nature. If a charge accelerates for a moment and then stops a disturbance in the electric field is sent out. This changing electric field creates a changing magnetic field and they continue to sustain each other, propagating infinitely outward. Now, if the source charge were to vanish there would still be a changing E/B field in its immediate vicinity which will continue to exist. Wouldn't this mean that the waves are emitted forever?
 
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  • #2
Nevermind. Stupid question.
 
  • #3
no, not a stupid question

Yes the EM wave continues to propagate outwards after the source stops emitting

not really too different than if you throw a pebble into a pond, the initially generated waves will still radiate outwards, even tho new waves are not being created at the source

Dave
 

Related to Electromagnetic wave emission after source vanishes

1. What happens to electromagnetic waves after the source disappears?

When an electromagnetic source vanishes, the waves it produced will continue to propagate through space until they are absorbed or reflected by another material.

2. Do electromagnetic waves disappear instantly when the source ceases to emit?

No, electromagnetic waves travel at the speed of light and will continue to propagate until they are absorbed or reflected, even after the source has stopped emitting.

3. Can the disappearance of an electromagnetic source have any effect on the waves it produced?

Yes, the disappearance of a source can affect the behavior of the electromagnetic waves. For example, the waves may change direction or be reflected differently if the source was a reflective surface.

4. How long do electromagnetic waves continue to travel after the source vanishes?

The duration of travel for electromagnetic waves after the source disappears depends on various factors such as the distance from the source, the type of wave, and the medium through which it is traveling. In some cases, the waves may continue to propagate for a very long time, while in others they may be quickly absorbed by the surrounding materials.

5. Is there any danger associated with electromagnetic waves from a vanished source?

In most cases, there is no danger associated with electromagnetic waves from a vanished source. The waves will continue to propagate until they are absorbed or reflected, but they will not cause harm unless they are extremely high-powered waves, such as those used in medical procedures or industrial applications.

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