Question

A convergent lens of power $16\text{D}$ is used as a simple microscope. The magnification produced by this lens, when the final image is formed at least distance of distinct vision is

• A. $4$
• B. $5$
• C. $6$
• D. $7$

Answer 1

The correct option is B $5$

Least distance of distinct vision $D=25\text{cm}=0.25\text{m}P=16\text{D}$
Magnification $m=1+\frac{D}{f}=1+PD.$
$m=1+(16\times 0.25)$
$m=1+4$
$m=5$