Brewster’s law

Definition

Brewster's law states that the angle at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection, is known as the Brewster angle. This occurs when the reflected and refracted light rays are perpendicular to each other.

5 Must Know Facts For Your Next Test

1. The Brewster angle can be calculated using the formula $\tan(\theta_B) = \frac{n_2}{n_1}$, where $n_1$ and $n_2$ are the refractive indices of the two media.
2. At the Brewster angle, reflected light is completely polarized perpendicular to the plane of incidence.
3. Brewster’s law only applies to unpolarized or partially polarized incident light.
4. For air-glass interfaces, typical values for the Brewster angle range around 56 degrees.
5. The concept is named after Scottish physicist Sir David Brewster who discovered it in 1815.

Review Questions

• What condition must be met for light to be perfectly transmitted through a surface according to Brewster's law?
• How do you calculate the Brewster angle using refractive indices?
• What happens to the polarization of reflected light at the Brewster angle?

Related terms

Polarization:

Orientation of oscillations in a transverse wave, especially in electromagnetic waves like light.

Refractive Index:

A measure of how much light bends when it enters a material from another medium.

Snell's Law:

$n_1 \sin(\theta_1) = n_2 \sin(\theta_2)$; describes how light rays bend when passing between different media.