Question

The magnifying power of an astronomical telescope is $8$, then the ratio of the focal length of the objective to the focal length of the eyepiece is : (final image is at $\infty$)

• A. $8$
• B. $\frac{1}{8}$
• C. $0.45$
• D. None of these

Answer 1

The correct option is A $8$

Magnifying power of telescope (M P)$=8$
The magnifying power of an astronomical telescope is $=\frac{focallengthofobject(-f_0)}{focallengthofeyepiece\left(f_e\right)}=8$
Hence, the ratio of the focal length of the objective to the focal length of the eyepiece is $8$.