# 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? – The Photon Aug 22 '15 at 15:36
• $n$ is a real number ( a glass ) – David 2000 Aug 22 '15 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. – Rob Jeffries Aug 22 '15 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/… – David 2000 Aug 23 '15 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).