Question

The resolving power of a telescope depends on :

• A. length of telescope
• B. focal length of objective
• C. diameter of the objective
• D. focal length of eyepiece

Answer 1

The correct option is C diameter of the objective

Resolving power of telescope $R=\frac{1}{\Delta \theta }=\frac{a}{1.22\lambda }$
where, $\Delta \theta$ is angular separation between two objects.
$a$ is the diameter of the objective.
$\lambda$ is wavelength of light.
So, clearly resolving power of a telescope depends on diameter of the objective.