Assuming the human pupil to have a radius of $0.25 \ cm$ and a comfortable viewing distance of $25 \ cm$,the minimum separation between two objects that the human eye can resolve at $500 \ nm$ wavelength is..... $\mu m$.

Two stars are $10$ light years away from the Earth. They are seen through a telescope of objective diameter $30\, cm$. The wavelength of light is $600\, nm$. To see the stars just resolved by the telescope,the minimum distance between them should be ( $1$ light year $= 9.46 \times 10^{15}\, m$) of the order of

The diameter of the objective of a telescope is $3.6 \ m$. The limit of resolution of the telescope for a light of wavelength $540 \ nm$ is

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

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.