Question

Two monochromatic interfering waves of equal amplitude 'a' superpose on a screen. If the phase difference between the waves pi/2, what is the resultant intensity?

Answer 1

The resultant intensity would indeed be zero, have a look at the re,ation below

the resuatnt intensity is written as'

I = 2I'(1 + cosδ) = 4I'cos²(d/2)

so, if d = π/2; cosδ = 0

thus, the resultant intensity would be , I = 0