The length of the compound microscope is `14 cm.` The magnifying power for relaxed eye is `25`. If the focal length of eye lens is `5 cm`, then the object distance for objective lens will be

Options

A. 1.8 cm
B. 1.5 cm
C. 2.1 cm
D. 2.4 cm

Answer

A

Explanation

L = `v_(o) + f_(e) rArr 14 = v_(o) + 5 rArr v_(o) = 9 `cm
`m = (v_(o))/(u_(o)) . (D)/(f_(e)) rArr 25 = (9)/(u_(o)) . (25)/(5)`
`u_(o) = 1.8 cm `.