Question

Huygens's concept of secondary wave

• A. allows us to find the focal length of a thick lens
• B. is a geometrical method to a find a wavefront
• C. is used to determine the velocity of light
• D. is used to explain polarisation

Answer 1

The correct option is B is a geometrical method to a find a wavefront

Huygens principle states that "Every point on a wave-front may be considered a source of secondary spherical wavelets which spread out in the forward direction at the speed of light. The new wave-front is the tangential surface to all of these secondary wavelets."

Thus it is geometrical method to find the wavefront.