Geometrical Optics Reflection Mirror Refraction Lens
Geometrical
Optics Reflection Mirror
Refraction Lens
 MIRRORA mirror is a device that forms an optical image by reflection, as distinguished from a lens, which forms an image by retraction. Any flat, polished material reflects at least some light and thus acts as an elementary mirror. |
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| Optical mirrors are of three basic types: the ordinary flat mirror, the concave mirror, and the convex mirror. Concave mirrors are also called converging mirrors, because they cause light reflected by them to come to a focus. The magnifying shaving mirror is of this type. Convex mirrors spread out their reflected light and are thus also called diverging mirrors. | |
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| The formation of images by mirrors is conveniently treated by means of ray diagrams. Rays from a point source, which may be a single point or any one point on the surface of a luminous object, strike a plane mirror and are reflected. Each ray obeys the law of reflection, which states that the incident and reflected rays make equal angles with the mirror. As a consequence, the reflected rays appear to originate from the image point, which is located symmetrically with respect to the mirror surface and the object. The image is called a virtual image, because the light rays do not actually originate from it; they only appear to do so.¡@ | |
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