When 2 waves meet at a point the resultant displacement of the waves at that point is equal to the sum of displacements of each of the individual waves
The result wave is formed from the effect of interference
Two waves are coherent when they are emitted from a constant and unchanging phase difference
They must have the same frequency
Path difference is the difference in displacement of 2 waves in terms of wavelenghts
Interference is the superposition of coherent waves
Coherent - Two waves are coherent when they have a constant phase difference
Phase difference - the difference in the displacements of two particles along a wave
x/Lander * 360
Constructive Interference (maxima) - both coherent waves reach at maximum displacement
Conditions:
The two coherent waves must have a phasedifference of 0 degrees or 360 degrees
Path difference between the two waves is a multiple of the wavelength n*lander
Destructive Interference (Minima) - Both coherent waves reach at minimum displacement
Conditions:
The two coherent waves must have phase difference of 180 degrees - must be in antiphase
Path difference between the two waves is (n+1/2) *lander