If a hollow sphere is cut into parts and the outer surface of the cut part is painted, then it becomes a mirror with its inner surface as the reflecting surface. This type of mirror is known as a concave mirror.
Light converges at a point when it strikes and reflects back from the reflecting surface of the concave mirror.
When the concave mirror is placed very close to the object, a magnified, erect, and virtual image is obtained.
The image formed by the concave mirror can be small or large and can be real or virtual.
When light hits a concave mirror they reflect inwards towards a focal point.
A spherical mirror, whose reflecting surface is curved inwards is called a concave mirror.
Concave lenses are thinner in the middle than at the edges.
The ray is reflected by the principal focus for a concave mirror.