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Mirror Types, Definition, Terms, and Formula

A mirror is a reflective object usually made of glass, or polished metal that reflects light rays fall on its surface towards the viewer, creating a image that appears to be behind the reflective surface.

Types of Mirrors

The following are the most common types of mirrors:

Plane mirror:

A plane mirror is a flat reflective surface that reflects light in a way that preserves the original image’s size, shape, and orientation. It is called a “plane” mirror because its reflective surface is flat and not curved like a concave or convex mirror. Plane Mirror is a common mirror used in household for grooming.

Convex mirror:

A convex mirror, also known as a diverging mirror, is a curved mirror with a reflective surface that bulges outward. The center of the mirror’s curvature is behind the mirror, and its reflective surface curves outward towards the viewer.

Convex mirrors have a wider field of view than flat or concave mirrors, making them useful in situations where a large area needs to be monitored or viewed, such as in car side mirrors or in security mirrors in stores. They are also used in telescopes and other optical devices to help create a larger field of view.

Concave mirrors:

A concave mirror, also known as a converging mirror, is a curved mirror with a reflective surface that bulges inward. The center of the mirror’s curvature is in front of the mirror, and its reflective surface curves inward away from the viewer.

Concave mirrors are used in a variety of applications, such as in telescopes, headlights, and dental mirrors, to focus light and create magnified images. They are also used to collimate light rays for scientific experiments.

Mirror Terminologies

1. Pole: The centre point of the mirror through which the principal axis passes through the mirror is called the pole. It is denoted by the alphabet
2. Principal axis: The straight line that will pass through the pole and the centre of curvature is called the principal axis.
3. Centre of curvature: The centre of the sphere of which the mirror or lens is a part is called the centre of curvature. It is denoted by C
4. Radius of curvature: The radius of the sphere of which the mirror or the lens is a part is called the radius of curvature. The Radius of Curvature is denoted by R
5. Focal point or focus: It is a point at which all the light rays meet and we get a sharp image.
6. Focal length: The distance from the pole to the focal point is called the focal length.