question_answer

In a compound microscope the focal length of objective lens is 1.2 cm and focal length of eye piece is 3.0 cm. When object is kept at 1.25 cm in front of objective, final image is formed at infinity. Magnifying power of the compound microscope should be:                         [JEE ONLINE 11-04-2014]

A)       200

B) 100

C) 400

D) 150

Correct Answer: A

Solution :

[a] Given:

From

Magnification at infinity,

( least distance of distinct vision) = 200

Hence the magnifying power of the compound microscope is 200