A plane wave, with wavelength λ=600nm, travels through a diffraction grating with 8-slit and the interference pattern on the screen is shown in Fig. below. The distance between the 8-slit and the screen is L=4m and the spacing between nearest neighboring slits is d=60μm.
(a) Find the spacing (Δy ) between the principal maxima on the screen.
(b) What are the phase difference (δ1 )and position (y1, relative to central peak y=0 )