To increase magnification power of refracting type Telescope, we should increase:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → the focal length of the objective
The magnifying power (M) of a refracting telescope is,
$M=\frac{f_o}{f_e}$ [$f_0$ = focal length of objective]
Hence, by increasing the focal length of the objective lens, one increases magnification.