The intensity at a secondary maximum of a single-slit diffraction pattern is less than the intensity at the central maximum chiefly because:
A)some Huygens wavelets sum to zero at the secondary maximum but not at the central maximum
B)the secondary maximum is further from the slits than the central maximum and intensity decreases as the square of the distance
C)the Huygens construction is not valid for a secondary maximum
D)the amplitude of every Huygens wavelet is smaller when it travels to a secondary maximum than when it travels to the central maximum
E)none of the above

Question

Quizplus · Accepted Answer

At the secondary maximum, there are destructive interferences between Huygens wavelets from different parts of the slit, causing some wavelets to sum to zero. This does not happen at the central maximum, where all wavelets arrive in phase and add up constructively.

The Intensity at a Secondary Maximum of a Single-Slit Diffraction