91Ó°ÊÓ

Phase differences between two waves for three different cases are provided in the given phasor diagrams

The phase difference between interfering waves for the formation of maxima

$\mathbf{∆}\mathit{ϕ}\mathbf{=}\mathbf{2}\mathit{n}\mathbf{π}\mathbf{}\mathbf{}\mathbf{n}\mathbf{=}\mathbf{0}\mathbf{,}\mathbf{1}\mathbf{,}\mathbf{2}\mathbf{,}\mathbf{3}\mathbf{.}\mathbf{.}\mathbf{.}$ .....(1)

Phase difference between interfering waves for the formation of minima

$\mathbf{∆}\mathit{ϕ}\mathbf{=}\left(2n+1\right)\mathbf{π}\mathbf{}\mathbf{}\mathbf{n}\mathbf{=}\mathbf{0}\mathbf{,}\mathbf{1}\mathbf{,}\mathbf{2}\mathbf{,}\mathbf{3}\mathbf{.}\mathbf{.}\mathbf{.}$ .....(2)

The phase difference in the first figure 2 can be represented by

$∆\mathrm{ϕ}=\left(2n+1\right)\mathrm{π},\mathrm{n}=0,1,2,3...$

This represents minima in the interference pattern and thus can correspond to points 3 and 5 on figure 1.

The phase difference in the first figure 2 can be represented by

$∆\mathrm{ϕ}=2n\mathrm{π}\mathrm{n}=0,1,2..$

This represents maxima in the interference pattern and thus can correspond to points 1 and 4 in figure 1.

The phase difference in the first figure 2 can be represented by

$∆\mathrm{ϕ}=n\frac{\mathrm{π}}{2},n=1,5,9...$

This represents points between maxima and minima in the interference pattern and thus can correspond to point 2 on figure 1.