A system like that shown in Figure 28-35 consists of N slits, each transmitting light of intensity I0. The light from each slit has the same phase and the same wavelength. The net intensity I observed at an angle u due to all N slits isIn this expression, ф = (2πd/λ) sin u, where l is the wavelength of the light.
(a) Show that the intensity in the limit θ ( 0 is I = N2I0. This is the maximum intensity of the interference pattern.
(b) Show that the first points of zero intensity on either side of Ñ„ = 0 occur at Ñ„ = 2Ï€/N and Ñ„ = -2Ï€/N.
(c) Does the central maximum (θ = 0) of this pattern become narrower or broader as the number of slits is increased? Explain.

sin(No/2)]2 = I sin(4/2)