A mirror is an object that reflects the light in the same angle as it receives from the object, obeying the laws of reflection. Mirrors are of three types
- Plain Mirror
- Concave Mirror
- Convex Mirror
Concave mirrors and convex mirrors are called spherical mirrors. If a part of the hollow sphere is cut and the outer surface is polished, then the mirror reflects from the inner surface. This type of mirror is called a concave mirror. If the inner surface is polished the mirror reflects from the outer surface. This type of mirror is called a convex mirror. Concave mirrors have many applications like in headlights, shaving mirrors and many more. A few important properties of concave mirrors are listed below.
Property 1: The incident ray which is parallel to the principal axis passes through the focus of the concave mirror.
Property 2: If the incident light passes through the focus then it gets reflected parallel to the principal axis.
Property 3: The incident light passing through the centre of curvature returns in the same path after reflection from the spherical surface.
Property 4: The distance from the pole(P) of the mirror to the focus is called the focal length. The focal length of the spherical mirror is half of its centre of curvature(C).
Property 5: A virtual image, erect and a bigger image is formed if the object is placed between the focus and the pole of the mirror.
Property 6: If the object is placed at the focus(F), a real inverted and a very large image is formed at infinity.
Property 7: A real, inverted and a magnified image is formed when the object is placed between the focus(F) and centre of curvature(C).
Property 8: Real, inverted and same size image is formed at the centre of curvature when the image is placed at the centre of curvature(C).
Property 9: If the object is placed between the centre of curvature and infinity then a real, inverted and smaller image is formed between the focus and centre of curvature.