At the end of Section 36.4, the following statements were made about an array of N slits.

Question:

At the end of Section 36.4, the following statements were made about an array of N slits. Explain using phasor diagrams, why each statement is true.
(a) A minimum occurs whenever Φ is an integral multiple of 2π,/N, except when Φ is an integral multiple of 2π (which gives a principal maximum).
(b) There are (N - 1) minima between each pair of principal maxima.