The magnifying power of an astronomical telescope is 8 and the distance between the two lenses is `54 cm`. The focal length of eye lens and objective lens will be respectively

Options

A. `6cm and 48 cm`
B. `48 cm and 6 cm`
C. `8 cm and 64 cm`
D. `64 cm and 8 cm`

Answer

A

Explanation

`f_(o)+f_(e)=54` and `(f_(o))/(f_(e))=m=8impliesf_(o)=8f_(e)`
`implies8f_(e)=f_(e)=54impliesf_(e)=(54)/(9)=6`
`impliesf_(o)=8f_(e)=8xx6=48`