For a plane wave approaching an obstacle with a rectangular opening,diffraction becomes important in which of the following circumstances?
A) the beam is coherent
B) one or more dimensions of the rectangular opening is near the wavelength of the source
C) both dimensions of the rectangular opening are larger than the wavelength of the source
D) only if the opening is circular

Question

Quizplus · Accepted Answer

Diffraction becomes significant when the dimensions of the opening are comparable to or smaller than the wavelength of the source. Therefore, if one or more dimensions of the rectangular opening is near the wavelength of the source, diffraction will occur. Coherence of the beam or the shape of the opening (circular or rectangular) is not relevant to this phenomenon.

For a Plane Wave Approaching an Obstacle with a Rectangular