Question

An astronomical telescope of magnifying Power 8
using two lenses spaced 45 cm apart. The
focal length of the lenses used

Answer 1

Answer:

Given, Fo +fe = 45 (1)

M = Fo / fe = 8

Fo = 8 fe (2)

putting (2) in equation (1) we get,

8fe + fe = 45

9fe = 45

fe = 9 cm

putting fe = 9 cm in equation (2) we get,

Fo = 8 × 9

= 72 cm.