Brewster's Angle: Reflection and Refraction Intensity

[quietrain]

ok, at brewster angle ,i know when unpolarized light incident on a quartz stack has only s polarized reflections and , s & p polarized refractions into the quartz.

but why is the intensity of refracted light 50% if quartz don't absorb light? is it due to the random nature of unpolarized light so on the average, its 50%?

also, how do i know what is the intensity of the s-light reflected and the s-light refracted with the p-light? am i suppose to use malus' law for the refracted part? but what will be my angle? 90? then what about the reflected part?

thanks

 

[Phrak]

Don't work your problem with a stack of quartz; that clutters things up. Focus on a single surface.

 

[quietrain]

ok if i work with only 1 piece, then how do i know the intensity of the reflected s-light? and the transmitted s and p light?