Question

What is Huygens principle?

Answer 1

1. The Huygens–Fresnel principle (named after Dutch physicist Christiaan Huygens and French physicist Augustin-Jean Fresnel) states that every point on a wavefront is itself the source of spherical wavelets, and the secondary wavelets emanating from different points mutually interfere.
2. Huygens Principle, also known as the Huygens–Fresnel principle, highlights the following wave propagation behaviour:
3. Secondary sources form wavelets similar to the primary source.
4. At any given time, the common tangent on the wavelets in the forward direction gives the new wavefront.
5. The wavefront is the sum of the spherical wavelets.
   
6. Huygens stated that light is a wave propagating through space like ripples in water or sound in air. Hence, light spreads out like a wave in all directions from a source. The locus of points that travelled some distance during a fixed time interval is called a wavefront.