An astronomical telescope uses two lenses of power 10 D and ID. What is its magnifying power in normal adjustment?

cbse
ray-optics

#1

As, $f_{ o }$ = 1/P = 1/10 = 0.1 m = 10 cm
$f_{ e }$ = 1/P =1/1 =1m = 100cm
Magnifying power in normal adjustment,
m=-$f_{ o }$/$f_{ e }$ = -10/100 = -0.1