Question

A man with normal near point $\left(25cm\right)$ reads a book with small point using a magnifying glass, a thin convex lens of focal length $5cm$.

• A. the closest distance at which he can read the book when viewing through the magnifying glass is $4.17cm$
• B. the farthest distance at which he can read the books when viewing through the magnifying glass is $5cm$
• C. the maximum and minimum magnifying power possible using the above simple microscope are 5 & 6.
• D. All the above

Answer 1

The correct option is A the closest distance at which he can read the book when viewing through the magnifying glass is $4.17cm$

This can be solved by using lens formula

$\frac{1}{f}=\frac{1}{u}+\frac{1}{v}$

here f=5cm ,u=-25cm

then v=4.17cm