The resolving power of a refracting type telescope can be increased by :
Answer & explanation
Correct answer: option 1
Resolving power of telescope is defined as the reciprocal of the smallest angular separation between two distant objects whose images are seen separately.
Resolving power of telescope RP = \frac{a}{1.22\lambda}$
where a is the diameter of objective lens of telescope.
$\Rightarrow RP \propto a$
Thus resolving power of telescope can be increased by increasing the diameter of objective lens of telescope.