Brewster's Angle

\tan\theta_B = \frac{n_2}{n_1}

θ_B =

n₁ =

n₂ =

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At one special angle the reflected and refracted rays are exactly perpendicular, and light polarized in the plane of incidence cannot reflect at all — everything that bounces off is polarized parallel to the surface. For water (n = 1.333) from air that angle is arctan(1.333) ≈ 53.1°. Polarized sunglasses are oriented to block exactly that component, which is why they kill the glare off a lake at low sun but do little at noon.

Brewster's Angle

\tan\theta_B = \frac{n_2}{n_1}

Where

$\theta_B$ = Brewster's angle
$n_1$ = Index of the incident medium
$n_2$ = Index of the reflecting medium

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Brewster's angle — Snell's Law of Refraction, Critical Angle for Total Internal Reflection
Index of the incident medium — Snell's Law of Refraction, Critical Angle for Total Internal Reflection
Index of the reflecting medium — Snell's Law of Refraction, Critical Angle for Total Internal Reflection

Part of this formula set

Refraction and total internal reflection

5 formulasSnell's law and the refractive index, with the critical angle, Brewster's angle and apparent depth that follow from bending light at a boundary.