# Homework Help: Light absorbtion equation?

1. Dec 12, 2005

### Fosock

Any help here would be appreciated so much..

Is there an equation that links distance of glass travelled through to light intensity on the other side?

Obviously, the light intensity will decrease as the light travels through greater amounts of glass, but is there an trend I am looking for with my results? Any pattern?

Any info on this would mean everything to me, I am seriously at the end of my tether with a really poor teacher that won't help me out as 'that's not what his department does'. I'm not even allowed to hand in a draft, isn't that kinda wierd? I might go to another teacher I reckon, seems kinda fishy.

Laters, thanks SO much to anything at all that comes back.. I am completely willing to pay for any help.. I can post cash if you live in England, if not let me know what to do if you want paying or anything.

2. Dec 12, 2005

### Meir Achuz

The intensity of light decreases by the equation
$I=I_0e^{-x/\delta}.\quad\delta$ is called the
"attenuation length". It is given by
$\delta=\sqrt{\frac{\epsilon}{\mu}}\left(\frac{c}{4\pi\sigma}\right)$ in Gaussian units). The derivation of this is a bit involved.