1 ) An object is placed at a distance of f/2 from a convex lens . The image will be ?
1 ) An object is placed at a distance of f/2 from a convex lens . The image will be : -
Solution : -
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 ) If tube length of astronomical telescope is 105 cm and magnifying power is 20 for normal setting , calculate the focal length of objective ?
Solution : -
L = 105 cm , m = 20 , Fo = ?
So , we have formula : — M = Fo / Fe ,
So , it will become : — Fo = 20 Fe .
Now we use 2nd formula : -
L = Fo + Fe ,
105 = Fe + 20 Fe ,
So , Fe =
