Question

An astronomical telescope has an angular magnification ofmagnitude 5 for distant objects. The separation between the objective and the eye-piece is 36 cms and the final image is formed at infinity. The focal length f₀ of the objective and fe of the eye piece are(a) f₀ = 45 cm and f2 = –9 cm(b) f₀ = 50 cm and $f_{e}$ = 10 cm(c) f₀ = 7.2 cm and $f_{e}$ = 5 cm(d) f₀ = 30 cm and $f_{e}$ = 6 cm

Answer 1

answer d

m = - fo / fe

fo = 5 fe

L = fo + fe

fe = 36/6 = 6 cm

fo = 30 cm