Question: The condition of constructive interference for two slits is the same as that for adiffraction grating. What are the advantages of using a diffraction grating over a two-slitsetup to disperse light? Explain.

at this position as well. At the nth order maxima, the light from slit B travels n wavelength farther than the light from slit A, so again, constructive interference occurs. na 2 X B 1 1 C D zeroth S NoINS 1 maxima 1 1 A nth 21 P maxima L Retina of n L your eye Diffraction scale Two slits Figure 1 Geometry of the two-slit interference experiment In Fig. 1 the line AC is constructed perpendicular to the line PB. Since the slits are very c linge D DD 11al That