A double slit diffraction pattern is formed on a distant screen using mercury green light of

Question

wavelength 546.1 nm. Each slit has a width of 0.1 mm. The pattern shows that the 4th order
interference maximum is missing.
a) What is the separation of the slits?
b) What is the intensity of the 2nd order interference maximum relative to the zero order
maximum?
c) Show that the number of bright fringes seen under the central diffraction peak is always
given by 2(a/b)-1, where a is the separation of the slits.