An astronomical telescope of ten fold angular magnification has a length of 44 cm. The focal length of the objective is:
Answer & explanation
Correct answer: option 2
Magnification is $ M = \frac{f_0}{f_e} = 10$
$ f_0 + f_e = 11f_e = 44cm \Rightarrow f_e = 4cm , f_0 = 40cm$
The correct answer is Option (2) → 40 cm