each point on a wave front is a source of secondary waves
The Huygens-Fresnel principle states that every point on a wavefront is a source of wavelets. These wavelets spread out in the forward direction, at the same speed as the source wave. The new wavefront is a line tangent to all of the wavelets.
new wave front is the forward envelope of the secondary waves
The Huygens-Fresnel principle states that every point on a wavefront is a source of wavelets. These wavelets spread out in the forward direction, at the same speed as the source wave. The new wavefront is a line tangent to all of the wavelets.
Rays are perpendicular to wave front
Relation between ray and wave front is Rays are perpendicular to wave front
resultant displacement is the vector sum of the displacements produced
According to superposition principle in relation to displacements produced by a number of waves resultant displacement is the vector sum of the displacements produced
same frequency and with a constant phase relationship
Two sources of light are coherent if they have same frequency and with a constant phase relationship