(b)
In a different setup, a diffraction grating with 500.0 lines/mm is illuminated at normal
incidence with yellow light from a sodium lamp (which is actually composed of two closely
spaced wavelengths at 589.00 nm and 589.59 nm). At what angles do the second order
maxima occur for each of the sodium emission lines?
(c)
A submarine periscope lens has a radius of 75 mm. Under ideal conditions and at a
wavelength of 550 nm, calculate what is the smallest detail it can resolve at a point on the
horizon 5.0 km away? Give your answer in centimetres.
