# Light Absorption of a glass

I've the $n$ (refractive index of the glass sheet ) and $t$ (the thickness of the glass sheet)

with this information, how can I find the amount light absorption of the glass sheet?

• Are you given n as a real or a complex number? Commented Aug 22, 2015 at 15:36
• $n$ is a real number ( a glass ) Commented Aug 22, 2015 at 16:37
• Then as I say below, there is no absorption, or at least none that you can describe with a real refractive index. Commented Aug 22, 2015 at 17:48
• Yes sir. U r right. I searched and studied about it and now I know what's the story. but sir I edited my another question, will you please see that ? physics.stackexchange.com/questions/201951/… Commented Aug 23, 2015 at 4:45

Of course, real materials do absorb/scatter light, but you need a complex refractive index to sort that out. Do you have a complex refractive index? If you do then the light is exponentially attenuated as it travels through the material, but the amount of intensity attenuation depends on the (vacuum) wavelength of the light, $\lambda$, and the path length through the glass, roughly as $\exp(-4\pi \kappa x/\lambda)$, where $\kappa$ is the imaginary part of the refractive index and $x$ is the path length (which will be $t$ for normal incidence, but larger for non-normal incidence).