In a Young’s double-slit experiment, the light used has wavelength λ=600nm. At a point P on the screen the path difference between the two waves arriving from the slits is Δx=1.80μm.
(a) Calculate the phase difference ϕ at point P.
(b) State whether the intensity at P is maximum, minimum, or neither. Justify your answer.
(c) Determine the order (value of n) of the fringe obtained at P if it is bright or the order of the dark fringe if it is dark.