Is this a assumption that one wavelenght is called 2 pi ??? if not then how it is said that one wavelenght is 2 pi only and why not some other value
A phase difference of 2pi can mean that otherwise waves are displaced by at least one wavelength … it must be an integer number of wavelengths.
What happens if the wavelengths of the waves are not the same though? It is still possible for the phasors representing the waves to differ by 2-pi… it would mean that the phasor has rotated all the way around at least once.