Question

The size of the image of an object by a mirror having a focal length of 20cm is observed to be reduced to one third of its size.At what distance the object has been placed from the mirror what is the nature of the image and the mirror

Answer 1

An image smaller in size can be formed both by a concave mirror as well as a convex mirror.

When image height and focal length are equal the lines drawn parallel to both points will meet at infinity. Hence the position of image will be at infinity means the position is indefinite.