Question

In a compound microscope, the focal lengths of two lenses are `1.5 cm` and `6.25 cm` an object is placed at `2 cm` form objective and the final image is formed at `25 cm` from eye lens. The distance between the two lenses is
A. `6.00cm`
B. `7.75cm`
C. `9.25cm`
D. `11.00cm`

Answer 1

Correct Answer - D
`v_(0) = (f_(0)u_(0))/(u_(0)-f_(0)) = (1.5xx2)/(2-1.5) = 6cm`
`u_(e) = (f_(e)D)/(f_(e)+D) =(6.25 xx 25)/(25+6.25) = 5cm`
`L = v_(0)+u_(e) = 6+5 = 11 cm`
(Distance between the lens is the length of tube)