An astronomical telescope has an angular magnification of magnitude `5` for distant object. The separation between the objective and eyepiece is `36cm` and the final image is formed at infinity. Determine the focal length of objective and eyepiece.

Answer

A, C, D

Explanation

For final image at infinity,
`M_(oo)=f_0/f_e` and `L_(oo)=f_0+f_e`
`:. 5=f_0/f_e`……..(i)
and `36=f_0+f_e`…………(ii)
Solving these two equations, we have
`f_0=30cm` and `f_e=6cm`