Optics Question 438
Question: Magnification of a compound microscope is 30. Focal length of eye-piece is 5 cm and the image is formed at a distance of distinct vision of 25 cm. The magnification of the objective lens is
[DPMT 2005]
Options:
A) 6
B) 5
C) 7.5
D) 10
Show Answer
Answer:
Correct Answer: B
Solution:
$ m=\frac{v _{o}}{u _{o}}( 1+\frac{D}{f _{e}} )=m _{o}( 1+\frac{D}{f _{e}} ) $
Therefore $ 30=m _{o}( 1+\frac{25}{5} )=m _{0}\times 6 $
Therefore $ m _{o}=5 $ .
