Yes, light is incident at Brewster's angle when it strikes a surface, and this angle is special because it results in perfectly polarized light when reflected.
Brewster's angle is the angle of incidence at which light with a particular polarization (the plane of polarization) is perfectly transmitted through a transparent dielectric surface, with no reflection. At this angle, the reflected light is completely polarized perpendicular to the plane of incidence.
Mathematically, Brewster's angle (\( \theta_B \)) can be found using the formula:
\[
\tan(\theta_B) = \frac{n_2}{n_1}
\]
where:
- \( n_1 \) is the refractive index of the first medium (usually air, with \( n_1 \approx 1 \)),
- \( n_2 \) is the refractive index of the second medium (like glass or water).
At Brewster's angle, the angle between the reflected and refracted rays is 90°, meaning that the reflected ray is completely polarized.
This phenomenon is often seen in photography and optics when glare needs to be reduced, such as through polarized filters.