Monochromatic light (wavelength = 450 nm) is incident perpendicularly on a single slit (width = 0.40 mm). A screen is placed parallel to the slit plane and on it the distance between the two minima on either side of the central maximum is l.8 mm.
(a) What is the distance from the slit to the screen?
(b) What is the distance on the screen between the first minimum and the third minimum on the same side of the central maximum?