Huygens - Fresnel principle Fresnel's assumptions visit at https://youtu.be/bchMgoq148k for explanation of the PPT.

2. Huygens - Fresnel Principle
Each point on a wavefront is a source of
secondary disturbance, and the
secondary wavelets emanating from
different points mutually interfere.

4. Fresnel’s Assumptions
1.A wavefront is divided into large number of zones
called Fresnel zones. Resultant effect at any point
(P) will depend on the combined effect of all
secondary waves emanating from various zones.
To see the resultant effect at point P :

5. Fresnel’s Assumptions
To see the resultant effect at point P :
2.Effect at a point due to a particular zone will depend
on the distance of the point from the zone.

6. Fresnel’s Assumptions
To see the resultant effect at point P :
3.It will depend up on obliquity factor / inclination
factor with reference to zone under consideration.
K(θ) ∝ 1 + cos θ