$($Question $10$ continued$)$

$($c$)$ Light from a point source is incident on the pupil of the eye of an observer. The diameter of the pupil is $2\mathrm{.}8mm.$

$($i$)$ Draw, on the axes, the variation with diffraction angle of the intensity of light incident on the retina of the observer.

$[2]$

$($ii$)$ Estimate, in rad, the smallest angular separation of two distinct point sources of light of wavelength $656nm$ that can be resolved by the eye of this observer.

$[2]$