Q. The magnifying power of an astronomical telescope is 10 and the focal length of its eye-piece is 20 cm. The focal length of its object will be
A) 200 cm
B) 2 cm
C) 0.5 cm
D) 0.5$\times 10^{- 2}$cm
Explanation
(a) $M = \frac{f_{o}}{f_{e}},10 = \frac{f_{o}}{20},f_{0} = 200\ cm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.