Magnification produced by astronominal telescope for normal adjustment is 10 and length of telescope is 1.1m. The magnification when the image is formed at least distance of distinct vision `(D = 25cm)` is-

Options

A. 6
B. 14
C. 16
D. 18

Answer

B

Explanation

(a) Magnification, M=`f_(o)/(f_(e))=10 or f_(o)=10f_(e)`
Given, `f_(e)+f_(o)=1.1m`
`f_(e)+10f_(e)=1.1xx100cm`
`11f_(e)`=110
`f_(e)=10`
Magnification least distance of sistinct vision
`M_(D)=f_(o)/(f_(e))(1+f_(e)/D)=10(1+10/25)=10(35/25)=14`