Question

To increase the magnifying power of a telescope,
$\left(i\right)$ Aperture of the objective has to be increased.
$\left(ii\right)$ Focal length of the objective has to be increased.
$\left(iii\right)$ Focal length of the eyepiece has to be increased.

• A. Only $\left(i\right)$
• B. Only $\left(ii\right)$
• C. $\left(i\right)$ and $\left(iii\right)$
• D. $\left(ii\right)$ and $\left(iii\right)$

Answer 1

The correct option is B Only $\left(ii\right)$

Magnifying power, $m=\frac{f_0}{f_e}$
So, $m$ increases when $f_o$ increases, and $f_e$ decreases

The aperture of the objective lens does not affect the magnifying power.

Hence, $\left(B\right)$ is the correct answer.