Two points separated by a distance of $0.1 \ mm$ can just be seen in a microscope when light of wavelength $6000 \ Å$ is used. If the light of wavelength $4800 \ Å$ is used,the limit of resolution will become: (in $mm$)

Large apertures of telescopes are used for

$A$ man can clearly see two poles at a distance of $11 \, km$. What should be the minimum distance between the poles in $m$?

The diameter of the objective of a telescope is $a$,its magnifying power is $m$,and the wavelength of light is $\lambda$. The resolving power of the telescope is:

Light of wavelength $\lambda$ is coming from a star. What is the limit of resolution of a telescope whose objective has diameter $r$?

Assertion : $A$ famous painting was painted by not using brush strokes in the usual manner,but rather a myriad of small colour dots. In this painting the colour you see at any given place on the painting changes as you move away.
Reason : The angular separation of adjacent dots changes with the distance from the painting.