An astronomical telescope of tenfold angular magnification has a length of 44 cm . The focal length

Question

An astronomical telescope of tenfold angular magnification has a length of 44 cm . The focal length of the objective is\

Professor PC Thomas Classes · Answer

(d) : Length of astronomical telescope $\left(f_{o}+f_{e}ight)=44 \mathrm{~cm}$ and ratio of focal length of the objective lens to that of the eye piece $\frac{f_{O}}{f_{e}}=10$\ From the given ratio, we find that $f_{o}=10 f_{e}$.\ Therefore $10 f_{e}+f_{e}=44$ or $f_{e}=4 \mathrm{~cm}$\ and focal length of the objective $\left(f_{o}ight)$ $$ =44-f_{e}=44-4=40 \mathrm{~cm} $$