Curved mirror

A curved mirror is a mirror with a surface that curves. The surface can be convex (bulging outward) or concave (recessed inward). Most curved mirrors are shaped like part of a sphere, but some have other shapes. One common shape is a parabolic reflector. These are used in tools like reflecting telescopes to show objects far away clearly. This is because spherical mirrors and lenses can create blurry images, a problem called spherical aberration.

Distorting mirrors are used for fun. They change how things look by stretching and squashing images. These mirrors can make you appear much bigger or much smaller, depending on your position. Convex mirrors are often used to keep people safe, such as in stores or parking lots, because they show a wider view than flat mirrors.

Convex mirrors

A convex mirror is a curved mirror where the reflective surface bulges outward. These mirrors reflect light outward and create images that are smaller than the actual object. Because the light spreads out after reflecting, convex mirrors are not used to focus light. The images they make are virtual, meaning they appear behind the mirror and cannot be shown on a screen.

Convex mirrors are commonly used in cars as the passenger-side mirror, often with a warning that objects in the mirror are closer than they appear. They are also found in hallways, hospitals, hotels, schools, and stores to give a wider view around corners. These mirrors are useful for safety because they show a larger area than a flat mirror, even though objects look smaller.

Effect on image of object's position relative to mirror focal point (convex)

Object's position (S), focal point (F)	Image	Diagram
S > F ,   S = F ,   S F,\ S=F,\ SF,\ S=F,\ S	Virtual Upright Reduced (diminished/smaller)

Concave mirrors

A concave mirror, or converging mirror, has a surface that curves inward. These mirrors reflect light to one focal point and can show different images depending on how far away the object is from the mirror. Because they gather and focus light, concave mirrors are called "converging mirrors."

Concave mirrors have many uses. They are used in reflecting telescopes and to make images bigger for tasks like applying makeup. They help focus light in devices such as torches, headlamps, and spotlights, and are important in laser construction. They are also used in dental mirrors and in the mirror landing aid systems of modern aircraft carriers.

Effect on image of object's position relative to mirror focal point (concave)

Object's position (S), focal point (F)	Nature of Image	Diagram
S (Object between focal point and mirror)	Virtual Upright Magnified (larger)
S = F {\displaystyle S=F} (Object at focal point)	Reflected rays are parallel and never meet, so no image is formed. In the limit where S approaches F, the image distance approaches infinity, and the image can be either real or virtual and either upright or inverted depending on whether S approaches F from its left or right side.
F (Object between focus and centre of curvature)	Real image Inverted (vertically) Magnified (larger)
S = 2 F {\displaystyle S=2F} (Object at centre of curvature)	Real image Inverted (vertically) Same size Image formed at centre of curvature
S > 2 F {\displaystyle S>2F} (Object beyond centre of curvature)	Real image Inverted (vertically) Reduced (diminished/smaller) As the distance of the object increases, the image asymptotically approaches the focal point In the limit where S approaches infinity, the image size approaches zero as the image approaches F

Mirror shape

Most curved mirrors are shaped like part of a sphere. This is the easiest way to make them and works well for many things. But sometimes, spherical mirrors can make blurry images because the light rays don’t all meet at one point after reflecting.

For better focus, especially with light coming from far away, a parabolic reflector can gather the light into a tighter spot. A toroidal reflector is a special type of parabolic mirror that has different focusing distances depending on the angle.

Analysis

The Gaussian mirror equation connects the distance of an object from a mirror, the distance of the image formed, and the mirror's focal length. For convex mirrors, images always look like they are behind the mirror. For concave mirrors, images can be real or look like they are behind the mirror, depending on how far the object is from the mirror.

Ray tracing helps find where an image forms. By drawing lines from the object to the mirror and following reflection rules, you can find the image's location and size. One line goes to the mirror's surface vertex and reflects at the same angle. Another line parallel to the axis reflects through the focal point. Where these lines meet shows where the image appears.