theory, proposed by Dutch physicist Christiaan Huygens
in 1678. It explains how waves propagate through space
and provides a basis for understanding various wave
phenomena like reflection, refraction, diffraction, and
interference.
Statement of Huygens' Principle:
> "Every point on a wavefront acts as a source of
secondary spherical wavelets, which spread out in all
directions with the same speed as the wave. The new
wavefront is formed by the tangential surface to these
secondary wavelets."
Key Terms:
1. Wavefront: A surface that represents points of a wave
that are in phase (e.g., all crests or all troughs).
2. Secondary Wavelets: Small spherical waves generated
by points on the wavefront.
3. Tangential Surface: The surface that envelopes the
secondary wavelets, forming the next position of the