Speed of light in dispersive medium

In summary, when light travels through water, it can scatter due to non-uniformities in the material, such as bubbles or impurities. This scattering causes the appearance of broken or dispersed light, but the overall impression is still one of straight line focused light propagation. This is because the amount of light scattered is relatively small in ordinary tap water. Refraction, on the other hand, is caused by the light moving from a material with a different refraction index, and is not related to absorption and emission.
  • #1
agentredlum
484
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If light scatters when propagating through (example) water then why does it appear to travel in straight lines.

Yes, i know pencils appear broken but the overall impression is of straight line focused light propagation, and that does not make sense to me from a 'scattering' point of view.

If light does not scatter, then what slows it down?

If it is due to absorption and emission, then why is the emission in the same direction as the absorption?

:smile:
 
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  • #2
Scattering is caused by the reflection of part of the light by non uniformities in the material. In glass of water there could be small bubble, impurities, or whatever that reflect part of the light in random directions. Only a small part of the light would be scattered in a glass of ordinary tap water, however one could add more impurities or blow bubbles with a straw and much more of the light would be scattered.

The refraction of light is a different effect is is caused by the light moving from a material with a different refraction index than it was just in. It is not due to absorbtion and emission, but due to interaction of the EM waves with the material.
 

1. What is the speed of light in a dispersive medium?

The speed of light in a dispersive medium refers to the speed at which light travels through a material that causes the light to slow down or change direction as it passes through. This can be due to factors such as the material's density or refractive index.

2. How does the speed of light in a dispersive medium differ from the speed of light in a vacuum?

The speed of light in a vacuum is a constant value of approximately 299,792,458 meters per second. However, in a dispersive medium, the speed of light can vary depending on the material's properties, and can be slower or faster than the speed of light in a vacuum.

3. What is the relationship between the speed of light and the refractive index of a dispersive medium?

The refractive index of a material is a measure of how much the speed of light is reduced when passing through it. The higher the refractive index, the slower the speed of light will be in that material. Therefore, the speed of light in a dispersive medium is inversely proportional to the refractive index.

4. Can the speed of light in a dispersive medium be faster than the speed of light in a vacuum?

No, according to Einstein's theory of relativity, the speed of light in a vacuum is the maximum speed at which any object can travel. Therefore, the speed of light in a dispersive medium cannot exceed the speed of light in a vacuum.

5. How does the speed of light in a dispersive medium affect the appearance of objects?

When light passes through a dispersive medium, it can be bent or refracted, causing objects to appear distorted or appear to be in a different location. This is why objects may appear differently when viewed through different materials, such as water or a prism.

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