Question

The focal length of the objective and the eye piece of a compound microscope are 2.0 cm and 3.0 cm, respectively. The distance between the objective and the eye piece is 15.0 cm. The final image formed by the eye piece is at infinity. The two lenses are thin. The distance in cm of the object and the image produced by the objective, measured from the objective lens, are respectively
A. `2.4` and `12.0`
B. `2.4` and `15.0`
C. `2.3` and `12.0`
D. `2.3` and `3.0`

Answer 1

Correct Answer - A
`L = v_(0)+f_(e)`
`15 = v_(0) + 3 rArr v_(0) = 12cm`
image by objective:
`(1)/(v_(0))-(1)/(u_(0))=(1)/(f_(0)) rArr (1)/(12)-(1)/(-u_(0)) = (1)/(2)`
`(1)/(v_(0)) = (1)/(2)-(1)/(12) = (5)/(12)`
`u_(0) = 2.4 cm`