Question

Resolving power of a telescope increases with

• A. Increase in focal length of eye piece
• B. Increase in focal length of objective
• C. Increase in aperture of eye piece
• D. Increase in aperture of objective

Answer 1

The correct option is D Increase in aperture of objective

The Resolving power of a telescope is given by

$R.P=\frac{b}{1.22\lambda }$

Where,
$b-$ Size of aperture of the objective lens
$\lambda$ - Wavelength of light

To increase the resolving power of telescope, we must use the objective lens with large aperture $\left(b\right)$.

An additional advantage of a large objective is that it will collect a greater amount of light, and images seen will be much brighter.

The stars, which are extremely far away, can also be seen using a telescope of large aperture.

Hence, option $\left(D\right)$ is correct.