Fig. 1.1 shows plane wavefronts passing through a gap. The wavefronts beyond the gap are semicircular. What can be deduced about the gap width?
Question 1 Report
Fig. 1.1 shows plane wavefronts passing through a gap. The wavefronts beyond the gap are semicircular.
What can be deduced about the gap width?
Answer Details
Diffraction is most pronounced when the gap width is approximately equal to the wavelength of the waves. When plane wavefronts pass through such a gap, they spread out in all directions behind the barrier, producing semicircular wavefronts.
If the gap were much larger than the wavelength, the waves would pass through with very little spreading and remain mostly plane. If the gap were much smaller than the wavelength, very little wave energy would pass through. The semicircular shape of the diffracted wavefronts indicates the gap width is about the same as the wavelength.
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