When a mirror reflects light, does it directly bounce off the light or absorb it to re-emit a light?

Specular reflection means that if the reflecting surface is smooth, when parallel incident light hits this reflecting surface, it will still reflect in one direction in parallel. This kind of reflection belongs to specular reflection.

Specular reflection refers to the reflection of reflected waves (electromagnetic waves, or sound waves and water waves) in a certain direction; The included angle (reflection angle) between the reflected wave direction and the normal of the reflecting surface is equal to the included angle (incident angle) between the incident wave direction and the normal of the reflecting surface, and the incident wave and the reflected wave are in the same plane. When taking pictures, it is necessary to avoid the specular reflection light from entering the camera lens. Because the specular reflection light is extremely strong, it will form a white bright spot on the photo, which will affect the appearance of the ground object itself in the photo.

Mirrors are made of glass. On the surface of the mirror, most of the light is transmitted without being reflected. But the difference between a mirror and a window glass is that the back of the mirror is coated with a metal film. Light is electromagnetic wave, and metal is conductive, so it is difficult for light to penetrate metal, so light is almost completely reflected on the metal surface. These reflected lights pass through the glass mirror again and are seen by us.

The glass of the mirror plays two roles here: as a window for light to pass through, it protects the metal on the back; Making the surface of the metal layer smooth and flat is beneficial to specular reflection, rather than undirected diffuse reflection.