Question

The focal length of objective lens is \(50cm\), focal length of eyepiece is \(5cm\), tube length is \(15cm\) and least distance of distinct vision is \(25cm\). Find the magnifying power of the microscope.

• A. \(2.0\)
• B. \(3.0\)
• C. \(1.8\)
• D. \(6.0\)

Hint:

For a compound microscope, \[ M=\frac{L}{f_o}\left(1+\frac{D}{f_e}\right) \] for final image at least distance of distinct vision.

Answer 1

The Correct Option is D

Using the microscope magnification formula \[ M=\frac{L}{f_o} \left(1+\frac{D}{f_e}\right) \] Given \[ L=15cm,\quad f_o=50cm,\quad f_e=5cm,\quad D=25cm \] \[ M= \frac{15}{50} \left(1+\frac{25}{5}\right) \] \[ = 0.3(6) \] \[ M=1.8 \] Hence \[ \boxed{(C)\;1.8} \]