Question

Centre of curvature of a concave mirror lies ……..
A) Behind it
B) In front of it
C) In its center
D) None

Answer 1

Hint: Concave mirror is a part of a spherical mirror. The center of curvature of a spherical mirror lies at the center sphere. The spherical mirror that is polished from the outside such that it is reflecting from the inside is known as a concave mirror. The center of curvature of the convex mirror lies behind the mirror.

Complete answer:
A concave mirror or a convex mirror are parts of a spherical shell which can be polished from inside to make it a convex mirror. When the spherical shell is polished from the inside, the mirror thus formed is a concave mirror.

In the case of a concave mirror, rays of light parallel to the principal axis will appear to converge on a point in front of the mirror. The point where all the rays converge is known as focal point or focus of the concave mirror.

The above given figure is a concave mirror. The point P is known as the pole of the mirror. The point C denotes the center of the curvature. Clearly, the center of curvature lies in front of the mirror and not behind the mirror.

Thus, option (B) is the correct option.

Note: The center of curvature of the convex mirror lies behind the mirror. Pole, focus and center of curvature lies on the same line hence they are collinear points. Center of curvature is not part of the mirror, rather it lies outside the mirror. Concave mirror and convex mirror can be formed from a single spherical glass by slicing it but polishing both the slices in the opposite manner.