Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

enter image description here

When light reaches a boundary between materials below the critical angle, some of it refracts and some of it reflects. For example, glass acts as a partial mirror with a dark background.

Assuming no light is lost in the process, how much of total light in the incident ray is refracted as a function of $\theta_1$ (but of course $\theta_c ,n_1,n_2$ and other properties of the materials will probably matter too (whether the reflection was hard or soft, for instance)).

Intuitively, the amount refracted seems to be maximum when $\theta=0$, so perhaps $A\cos(\pi\frac{\theta}{\theta_c})$ is a viable function for the fraction refracted when $\theta > \theta_c$.

I hope there's an explanation that doesn't explain this away with a single experimental constant associated with each material (that is, is theoretically derived).

share|improve this question
add comment

1 Answer

up vote 4 down vote accepted

You are looking for the Fresnel equations. (See, e.g., http://physics.gmu.edu/~ellswort/p263/feqn.pdf for a derivation.)

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.