physics GRE-astronomy/optical help-stat help

[evank15]

I have no idea what the second question is asking, but the first one is simple. Just have to know what formula to use.

The (angular) resolution limit is known as the Rayleigh Criterion.

This limit, x, is a function of the diameter of the telescope and the wavelength of light.

sin(x) = 1.22k/D

where k is the wavelength of light and D is the diameter of the telescope. Invoking the small angle approximation (extremely valid here), sin(x) ~ x, we get for the formula you want:

D = 1.22k/x

D = 1.22(600E-9)/(3E-5)

D = 2.44cm