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

Length of compound microscope,
`L_(oo)=v_(o)+f_(e )rArr 14 v_(o)+5`
`therefore " " v_(o)=9 cm`
Mgnifying power of microscope for relaxed eye
`M=(v_(o))/(u_(o)).(D)/(f_(e ))` or `25=(9)/(u_(o)).(25)/(5)`
or distant of object, `u_(o)=(9)/(5)=1.8 cm`