wave optics equations
Answers
Answer:
hey ☺
Revision Notes on Wave Optics
Huygens Principle:- Wave-front of a wave, at any instant , is defined as the locus of all the particles in the medium which are being disturbed at the same instant of time and are in the same phase of vibration.
(a) Each point on a wave front acts as a source of new disturbance and emits its own set of spherical waves called secondary wavelets. The secondary wavelets travel in all directions with the velocity of light so long as they move in the same medium.
Huygens Principle(b) The envelope or the locus of these wavelets in the forward direction gives the position of new wave front at any subsequent time.
Determination of Phase Difference:-
The phase difference between two waves at a point will depend upon
(a) The difference in path lengths of the two waves from their respective sources.
(b) The refractive index of the medium
(c) Initial phase difference between the source if any.
(d) Reflections, if any, in the path followed by waves.
A point will be a minima if the two waves reaching there have a path difference of odd multiple of λ/2.
Imin = K. 4a2×0 = 0
Condition for constructive interference:-
Path difference = (2n)λ/2
Phase difference = (2n)π
Condition for destructive interference:-
Path difference = (2n+1)λ/2
Phase difference = (2n+1)π
Coherent Sources:- Coherent sources are the sources which either have no phase difference or have a constant difference of phase between them.
Conditions for interference:-
(a) The two sources should emit, continuously, waves of same wavelength or frequency.
(b) The amplitudes of the two waves should be either or nearly equal
(c) The two sources should be narrow.
(d) The sources should be close to each other.
(e) The two sources should be coherent one.