A green laser beam (λ=532nm) passes through a single rectangular slit that is 5.0μm wide before striking a distant screen. A student must decide whether to model the propagation after the slit with rays or with waves. Which of the following justifications is most appropriate?
(a) Use the ray model because the slit width is much larger than the wavelength, so diffraction can be ignored.
(b) Use the wave model because the narrow slit will cause the beam to refract, which requires a wave description.
(c) Use the wave model because the slit width is only an order of magnitude larger than the wavelength, so diffraction will strongly affect the beam.
(d) Use the ray model because the laser is coherent and monochromatic, eliminating interference effects.