Question

The magnification of an image by a convex lens is positive only when the object is placed

• A. at its focus $F$
• B. Between $F$ and $2F$
• C. at $2F$
• D. between $F$ and optical centre

Answer 1

Answer: (D)

between $F$ and optical centre

Answer 2

The magnification of an image by convex lens is positive only when the object is placed between focal point $(F)$ and optical centre because image formed by the convex lens for this location of the object is virtual and magnified and for real image $m=-$ ve. For virtual image, $m=+ ve$