Question

The focal length of objective and eye lens of a microscope are `4 cm` and `8 cm` respectively. If the least distance of distinct vision is `24 cm` and object distance is `4.5 cm` from the objective lens, then the magnifying power of the microscope will be
A. 18
B. 32
C. 64
D. 20

Answer 1

Correct Answer - B
(b) For objective lens,
`1/(f_(o))=1/v_(o)-1/u_(o)`
or `1/4=1/v_(o)-1/((-4.5))rArrabs(v_(o))=36 cm`
`therefore` Magnifying power, `abs(M)=u_(0)/v_(0)(1+D/(f_(e)))=36/4.5(1+24/8)=32`