Light Scattering Question

[deleted927298]

Passage: Two samples marked tube A and tube B consist of identical molecules of differing concentrations of gas light of one wavelength of differing concentrations of gas. Light of one wavelength scatters off of Tube A more completely than another gas of another wavelength on Tube B.

The speed of light in Tube A is greater than that in Tube B.

The TBR says if the speed of light is greater in Tube A, then there is less light scattering in Tube A.

My Q: What is the relation between light scattering and speed of light? Does this mean that more light scattering will decrease the speed of light due to the increased concentration of substance in the medium that causes more light scattering?

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[SonhosDaVida]

Mmm..... I think the logic is sound

 

[deleted927298]

bump

 

[deleted927298]

bump

 

[PositivePhotoresist]

Scattering of light will cause changes in the momentum and energy of the light. If the light is traveling faster in one medium, that means there is less impedance from particles of gas that alters the momentum or energy of the light. Think about light as a wave in this case. It’s continuous to an extent like the ocean waves. What happens when the ocean waves hit some rocks? The waves get restricted from going faster than it wants to because of this interference. The same could be thought about with light and gas molecules here.

Refraction is a type of scattering. Let’s try to mathematically relate refraction to the speed of light in a new medium.
Define l as wavelength in a new medium and lo as wavelength in a vacuum. We have: lo/l = (c/f)/(v/f) = c/v = n. Experimentally, we know that the frequency of the light doesn’t change when shifting mediums. Rearrange for v to get v = c/n. We have c, the speed of light in a vacuum (a constant), and n, the index of refraction. The greater n is, the more light that gets refracted (or scattered). We see that if v (the speed of light in a new medium) gets larger, than n has to get smaller, thus implying a lower degree of scattering.