Are light waves/ EM waves damped?

In summary, light traveling through empty space does not lose strength, although it does spread out. The concept of "tired light" is not accurate, as energy is not damped over distance. Rather, the decrease in amplitude is due to the energy being spread out over a wider area. This can be seen with a collimated light source, such as a laser, which maintains its intensity over long distances. When considering the light from a star reaching our eyes, only a small fraction of photons actually make it, as the area of our pupil is much smaller than the area of a sphere with a radius equal to the distance to the star.
  • #1
Arup Biswas
34
2
We can't see objects from objects far away from us. Why? I think light waves damps! When it reaches our eyes it's amplitude is too small to be visualised! Is this true? If indeed EM waves are damped then why? If not please give a suitable definition for the mentioned phenomena too !
 
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  • #2
Light traveling through empty space does not lose strength (although it does spread out). The wikipedia article on "tired light" is a good start.
 
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  • #3
Arup Biswas said:
We can't see objects from objects far away from us. Why? I think light waves damps! When it reaches our eyes it's amplitude is too small to be visualised! Is this true? If indeed EM waves are damped then why? If not please give a suitable definition for the mentioned phenomena too !

It is not damped. It is because the energy gets spread out over a wider area that the amplitude becomes small (in QM terms, the number of photons per unit area becomes smaller) as it goes further from the source. Why do you think a light bulb is harder to look at with your eyes when you are an inch away, versus when you are 100 meters away?

If you have a plane wave, collimated light source, such as a laser, then the intensity or brightness can be preserved over longer distances, and it will be as bright 1 inch away as well as 100 meters away. This, this is easily an indication that there is no intrinsic damping.

Zz.
 
  • #4
Thanks ZZ I got your point [emoji5][emoji5] At least for now this much will help me to progress [emoji5]
 
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  • #5
You can work out what fraction of the light from a star reaches your eye. It's the area of your pupil divided by the area of a sphere with a radius equal to the distance to the star. It's a wonder any photons make it.
 

Related to Are light waves/ EM waves damped?

1. What is damping in relation to light waves/EM waves?

Damping is the process by which the energy of a light wave or EM wave decreases as it travels through a medium. This can be caused by various factors such as absorption, scattering, or conversion of energy into other forms.

2. How does damping affect the intensity of light waves/EM waves?

Damping causes the intensity of light waves/EM waves to decrease as they travel through a medium. This means that the amplitude of the wave decreases, resulting in a decrease in the brightness or strength of the wave.

3. What factors can cause damping in light waves/EM waves?

There are several factors that can cause damping in light waves/EM waves, including absorption by the medium, scattering due to interactions with particles in the medium, and conversion of energy into other forms such as heat.

4. Can damping be avoided in light waves/EM waves?

In most cases, it is not possible to completely avoid damping in light waves/EM waves as they travel through a medium. However, the amount of damping can be minimized by using materials that have low absorption and scattering properties.

5. How does the type of medium affect the damping of light waves/EM waves?

The type of medium that the light waves/EM waves travel through can have a significant impact on the amount of damping that occurs. For example, materials with high density and high optical density tend to have higher levels of damping compared to materials with lower densities and optical densities.

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