Question

the radius of curvature of plane mirror is at infinity.explain

Answer 1

When a surface is perfectly a straight line like that of a plane mirror, we consider the radius of curvature to be at infinity as we can think of the plane mirror as a very very small segment of a very very large circle whose radius is very large that we consider is it to be a very large distance (infinity). If we zoom in to a segment of a circle , we find that at a considerable zoom, that segment appears to be a straight line.

Answer 2

The plane mirror has to be taken as a very very small part of a spherical mirror.

Therefore the radius of curvature will be very very large that we will have to consider it to be at infinity.

So the radius of curvature of a plane mirror is at infinity.