Question

Linear magnification produced by a convex lens can be:

• A. Less than 1 or more than 1
• B. Less than 1 or equal to 1
• C. More than 1 or equal to 1
• D. Less than 1, equal to 1 or more than 1

Answer 1

The correct option is D

Less than 1, equal to 1 or more than 1

Explanation for the correct option

Option (D)

1. We know that linear magnification of a lens is given by the formula, $m=\frac{v}{u}$, where v and u are the image distance and object distance, respectively.
2. Considering f as a focal length of the lens.
3. When the object is placed at a distance greater than 2f from the lens, then an image will be produced on the other side between the distance of f to 2f. In this case, the object distance $>$ image distance, so magnification, m$<$1.
4. When the object is placed at a distance of 2f, then an image will be produced on the other side at a distance 2f. In this case, object distance = image distance, so magnification, m =1.
5. When the object is placed at a distance of f to 2f from the lens, then an image will be produced on the other side at a distance greater than 2f. In this case, the object distance $<$ image distance, so magnification, m$<$1.

Diagrams

magnification > 1 magnification = 1 magnification < 1

So, Linear magnification produced by a convex lens can be Less than 1, equal to 1, or more than 1.

Hence, option (D) is correct.