Question

The focal lengths of the objective and eye lens of telescope are respectively $200cm$ and $5cm$. The maximum magnifying power of the telescope will be.

• A. $-40$
• B. $-48$
• C. $-60$
• D. $-100$

Answer 1

The correct option is B $-48$

Magnifying power of astronomical telescope
$m=-\frac{f_o}{f_e}(1+\frac{f_e}{D})=-\frac{200}{5}(1+\frac{5}{25})=-48$.