The least resolvable angle by a telescope using objective of aperture 5 m is nearly `(lambda = 400 Å)`

Whatis theminimumangularseparation between two stars if a telescope is used to observe them, with an objective of aperture 20 cms. ( lambda = 5900 overset@A )

Calculate the smallest angle resolved by a telescope with an objective of 5.0m diameter. What minimum magnification is needed to enable the human eye to utilize the resolution? (Aperture of the eye =2.5 mm, lambda= 5500 dotA ).

What is the resolving power of a telescope whose objective lens has a diameter 1.22 m from a wavelength 4000 Å?