Question

A magnifying glass has f $=$ 12 cm. To produce maximum angular magnification the object should be placed at a distance of (Least distance of clear vision $=$ 25 cm):

• A. 71 cm
• B. 68 cm
• C. 8.4 cm
• D. 8.1 cm

Answer 1

Answer: (D)

8.1 cm

Since least distance of clear vision = 25 cm
So $v=+25cm$
$f=-12cm$
Using
$\frac{1}{v}-\frac{1}{u}=\frac{1}{f}$
$\frac{1}{25}-\frac{1}{u}=\frac{1}{-12}$
$u=8.1cm$