For light with a wavelength of 600 nanometres, what are the conditions for destructive interference at point P?
Equation
1) The path difference should be an odd number (1,3,5,7...) multiple of half the wavelength.
2) The path dissimilarity must be a whole number multiple of the wavelength.
3) The path difference should be one fourth the wavelength.
4) The path dissimilarity must be 1.