Optical properties of cosmetic mirrors

The reflection of light by a specular surface obeys the law of reflection. Its reflectivity depends on the angle of incident light, the smoothness of the mirror surface and the properties of the metal film coated. The imaginary line perpendicular to the mirror surface is called the normal, and the angle between the incident ray and the normal is equal to the angle between the reflected line and the normal. The object in front of the plane mirror forms an upright virtual image behind the mirror, and the distance between the image and the mirror is equal to the distance between the object and the mirror. If you want to see your entire body length from the mirror, since the angle of incidence is equal to the angle of reflection, the mirror must be at least half your length. The reflecting surface of a concave mirror is oriented towards the center of curvature. The parallel light incident on the concave mirror is reflected and concentrated to the focal point (f). If the cooker is placed at the focal position of the large concave mirror, it can be heated by concentrated sunlight and become a solar cooker. For example, in a car lamp or a searchlight, the light source is placed at the focal position of the concave mirror to reflect the parallel light. Objects outside the center of curvature can be reflected into an upside-down real image, such as a reflecting telescope. The reflective surface of the convex mirror faces away from the center of curvature, and the object becomes a reduced upright image behind the mirror, which can reflect a wide range of reduced landscapes, such as a car rearview mirror