Interference and Phase Difference
Consider shifting one of the waves by a distance ? relative to the other
they add up constructively
corresponds to a phase shift by ?? = 2?
constructive interference for ?? = m2?
or path difference ?L= m ?
a shift by ?? = ? corresponds to a shift of one of the waves by ? /2
destructive interference for ?? = (2m+1)?
or path difference ?L= (2m+1) ? /2