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Question
According to Huygens’s principle, the amplitude of secondary wavelets is ______.
Options
equal in both the forward and the backward directions.
maximum in the forward direction and zero in the backward direction.
large in the forward direction and small in the backward direction.
small in the forward direction and large in the backward direction.
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Solution
According to Huygens’s principle, the amplitude of secondary wavelets is maximum in the forward direction and zero in the backward direction.
Explanation:
According to Huygens’s principle, every point on a wavefront acts as a source of secondary wavelets that spread out in all directions with the same speed as the original wave.
However, in practice:
- The amplitude of secondary wavelets is maximum in the forward direction (the direction of wave propagation).
- It is zero in the backward direction, meaning no wave travels backward.
This is because the backward wavelets interfere destructively, and the forward wavelets combine constructively to form the new wavefront.
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