What happens to the amount of incident light reflected if the angle of incidence is increased?

Question

What happens to the amount of incident light reflected if the angle of incidence is increased?

Answer 1

Generally it increases. See the ref. For light passing from a denser to a less-dense medium (N1>N2), reflection is at a minimum value (4% for glass-air) at 0 deg incidence and increases up to a critical angle above which total internal reflection occurs. For N1<N2, reflection is a function of E-field polarization. With out-of-plane polarization, reflection Rs continuously increases with increasing angle of incidence. With in-plane polarization, reflection Rp decreases until it reaches 0 at Brewster's angle, then increases. For glass with N2=1.5, total reflection of unpolarized light (=(Rp+Rs)/2) increases almost continuously (but with some variation around Brewster's angle) from 4% at 0 deg to 100% at 90 deg..