Mirrors

• Mirrors

For a real object very far away from the mirror, the real image is formed at the focus.

For a real object close to the mirror but outside of the center of curvature, the real image is formed between C and f. The image is inverted and smaller than the object.

For a real object at C, the real image is formed at C. The image is inverted and the same size as the object.

For a real object between C and f, a real image is formed outside of C. The image is inverted and larger than the object.

For a real object at f, no image is formed. The reflected rays are parallel and never converge.

For a real object between f and the mirror, a virtual image is formed behind the mirror. The position of the image is found by tracing the reflected rays back behind the mirror to where they meet. The image is upright and larger than the object.

A convex mirror, fish eye mirror or diverging mirror, is a curved mirror in which the reflective surface bulges toward the light source. Convex mirrors reflect light outwards, therefore they are not used to focus light. Such mirrors always form a virtual image, since the focus F and the centre of curvature 2F are both imaginary points "inside" the mirror, which cannot be reached. Therefore images formed by these mirrors cannot be taken on screen. (As they are inside the mirror) A collimated (parallel) beam of light diverges (spreads out) after reflection from a convex mirror, since the normal to the surface differs with each spot on the mirror.

The image is always virtual (rays haven't actually passed through the image), diminished (smaller), and upright. These features make convex mirrors very useful: everything appears smaller in the mirror, so they cover a wider field of view than a normal plane mirror does as the image is "compressed".

• Concave spherical mirror — 4431.00
• Convex spherical mirror — 4435.00

• What does “virtual image” mean?