Question

When used at a wavelength of 1 micron, a telescope can resolve angles as small as 0. 1 seconds of arc. How small an angle could the telescope resolve when used at a wavelength of 5 microns?

Answer 1

θ = 1.22 λ / D

Above is the formula calculated for a circular aperature

If the wavelength is multiplied by 5 then the angle of resolution would be 5 times as great or 5 * θ

5 * θ = .5 seconds