An Interference Pattern Is Produced By Four Parallel And Equally Spaced Narrow Slits 2840871

An interference pattern is produced by four parallel and equally spaced narrow slits. By drawing appropriate phasor diagrams, explain why there is an interference minimum when the phase difference f from adjacent slits is (a) p>2; (b) p; (c) 3p>2. In each case, for which pairs of slits is there totally destructive interference?