1. A square shaped aperture (1mm x 1mm) is placed against a lens with a focal length of 10 cm. A plane wave with a wavelength of 1um incident normally on this aperture. (1) Please calculate and plot the intensity distribution at the focal plane. (2) Where are the locations of the first dark bands (3) Assume the intensity of the brightest region you detect is I, now if you change the current lens to a new lens with a focal length of 5cm, how is the light intensity change in the brightest region (express your answer with Io)