Question

Under which of the following conditions a concave mirror can form an image larger than the actual object ?

• A. When the object is kept at a distance equal to its radius of curvature
• B. When object is kept at a distance less than its focal length
• C. When the object is placed between the focus and centre of curvature
• D. When object is kept at a distance greater than its radius of curvature

Answer 1

Answer: (B), (C)

When the object is placed between the focus and centre of curvature

Explanation for the correct option:

• Option (B)

An object at a distance lesser than the focal length forms an image of larger size than the object as well as erect and virtual.

• Option (C)

An object between the center of curvature ‘C’ and focus ‘F’ forms an image that will appear beyond the center of curvature. It will be real as well as inverted. The image will appear to be larger than the object.

Explanation for incorrect options:

• Option (A)

An object at ‘C’ or at a distance equal to the radius will form an image of equal size.

• Option (D)

The image will appear inverted and smaller than object size and will form in between ‘C’ and ‘F’.

Thus, the image size will be larger than the actual object size if the object is placed in between ‘C’ and ‘F’ and in the second case if it is placed between ‘F’ and ‘P’ of a concave mirror.

Hence, both options (B) and (C) are the correct options.