An astronomical telescope has an angular magnification of magnitude 5 for distant object. The separation between the objective and the eyepiece is 36 cm and the final image is formed at infinity. The focal length `f_(0)` of the objective and the focal length `f_(0)` of the eyepiece areA. `f_(o)=45 cm and f_(e)=-9cm`B. `f_(o)=-7.2 cm and f_(e)=5cm`C. `f_(o)=50 cm and f_(e)=10cm`D.

An astronomical telescope has an angular magnification of magnitude 5

1.	An astronomical telescope has an angular magnification of magnitude 5 for distant object. The separation between the objective and the eyepiece is 36 cm and the final image is formed at infinity. The focal length `f_(0)` of the objective and the focal length `f_(0)` of the eyepiece areA. `f_(o)=45 cm and f_(e)=-9cm`B. `f_(o)=-7.2 cm and f_(e)=5cm`C. `f_(o)=50 cm and f_(e)=10cm`D.
Answer» Correct Answer - D (d) In this case, `abs(m)=f_(0)/(f_(e))=5` and the length of telescope = `f_(0)+f_(e)=36` On solving Eqs. (i) and (ii), we get `f_(e)=6 cm, f_(0)=30 cm`

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