Answer:
For destructive interference phase difference is
[tex](2n+1)\pi[/tex] where n∈ Whole numbers
Explanation:
For sinusoidal wave the interference affects the resultant intensity of the waves.
In the given example we have two waves interfering at a phase difference of [tex]\frac{\pi}{4}[/tex] would lead to a constructive interference giving maximum amplitude at at the RMS value of the amplitude in resultant.
Also the effect is same as having a phase difference of [tex]( \frac{\pi}{4} + 2\pi)[/tex] because after each 2π the waves repeat itself.
In case of destructive interference the waves will be out of phase i.e. the amplitude vectors will be equally opposite in the direction at the same place on the same time as shown in figure.
They have a phase difference of [tex]\pi[/tex] or which is same as [tex](2\pi+\pi)[/tex]
Generalizing to:
a phase difference of [tex](2n+1)\pi[/tex] where n∈ {W}
{W}= set of whole numbers.