Light is an electromagnetic wave. When it meets the interface between different media, it will be reflected. Mirror is a smooth surface, usually with a metal film on the back of the glass sheet or a metal film on the front of the glass. On the surface of the mirror, light will reflect when it meets the metal film, so that we can see the image in the mirror.

The principle of light reflection can be divided into two main aspects: plane mirror and curved mirror.

1. Plane mirror: Plane mirror is the simplest kind of mirror, and its reflection principle is based on plane reflection. According to the reflection law of light, the incident angle is equal to the reflection angle, and the incident angle and reflection angle of light on the plane mirror are equal. When the light is perpendicular to the plane mirror, the reflected light is still perpendicular to the mirror. When the light is incident obliquely, the reflected light will be inclined at equal angles to form an image in the mirror.

2. Curved mirrors: Curved mirrors are divided into concave mirror and convex mirrors. The reflection principle of concave mirror (such as concave lens) and convex mirror (such as convex lens) is based on spherical reflection. The law of spherical reflection is different from that of plane reflection, which involves the bending and focusing of light when it passes through a curved surface. In a concave mirror, the reflected light will converge and focus on one point, while in a convex mirror, the reflected light will diverge.

Application of reflection principle

1, vehicle rearview mirror: The rearview mirror of cars and motorcycles uses the reflection principle to let the driver observe the situation behind the vehicle while driving. These mirrors are usually convex mirrors. By adjusting the curvature of the rearview mirror, the field of vision can be expanded, making it easier for the driver to perceive the traffic situation behind him.

2. Projector: The reflection principle is widely used in projectors. By using a mirror or a reflective screen, the projector can project light onto the screen to form a clear image. This technology has been widely used in education, business and entertainment.

3. Solar reflector: Solar reflector focuses sunlight on one point according to the reflection principle, which is used to heat the working medium in the solar power station, thus generating high-temperature steam and driving the turbine to generate electricity.

4. Laser technology: In the laser, the optical cavity is constructed by using the reflection principle to amplify the laser. After many reflections in the cavity, the light gradually strengthens, and finally forms a powerful and focused laser beam, which is used in various scientific, medical and industrial fields.