State Huygens' principle of diffraction of light.

How is a wavefront defined? State Huygen's principle of propagation of light wave.

State Huygen's principle of propagation of light and prove the laws (Snell's law) of refraction on its basis.

State Huygen's principle for propagtion of light wave .

According to Huygens' principle, during rafraction of light from air to a denser medium

According to Huygens' principle, during refraction of light from air to a denser medium

According to Huygens' principle, during rafraction of light from air to a denser medium

Write Huygen's principle.

With the help of a diagram,explain the Huygens' principle for the propagation of light in a medium.