Explain the Huygen's construction of plane wavefront in easy and simple way !!!

Here we know all about, the construction of the plane wavefront.

So let's come to know,

i) The plane wavefront is formed when the point of observation is very far away or we can say at infinity from the primary source of light.

ii) So here let's PQR represent a plane wavefront at any instant.

So according to the Huygen's principle, all the points on this wavefront will act as a secondary source of light and sending out secondary wavelets in the forward direction only.

iii) For make it to undestand easily, first of all we need to draw hemisphere with Point P,Q,R.... as centres and 'ct' as a radius.

The surface tangential to all such hemisphere is P1Q1R1....at instant 't'.

The new wavefront at time 't'.

iv) The plane wavefront is propagated or travel as a plane waves in the homogeneous isotropic medium. Therefore they are parallel to each other.

v) PP1N1, QQ1N2, RR1N3 these are the wave normal at point P,Q,R respectively.

These wave normal shows the direction of propagation of the plane wavefront.

vi) The new wavefront P1Q1R1 is parallel to the primary wavefront PQR.

THE END

Thank you....!!!!