Question

A convex lens of focal length $5cm$ is used as a simple microscope. The magnification produced for normal visions is equal to

• A. $12.5$
• B. $13.5$
• C. $11.5$
• D. $6$

Answer 1

The correct option is D $6$

$\begin{array}{c}\text{In a simple microscope at normal vision}\\ \text{(image at infinity) magnification}=\frac{D}{f}\\ \text{where}\\ \begin{array}{cc}D& =\text{least. Distance of distict vision}\\ f=\text{focal length of lens}& \\ D=30cm& \\ f=5cm& \\ \text{magnification}=\frac{30}{5}=6& \end{array}\\ \begin{array}{c}\text{So option D}\text{is correct.}\end{array}\end{array}$