Conditions for constructive and destructive interference of waves from two sources (13-15)

Question 1 of 2

Question

Wavelength

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Review

If the path length difference $\Delta_{\mathrm{pl}}$ is neither a whole number of wavelengths nor an odd number of half-wavelengths, the interference is neither completely constructive nor completely destructive (Figure 13-10c). Because interference of the surface waves occurs at all points in Figure 13-11, we call the overall pattern in that figure an $\textbf{interference pattern}$ .

Here’s a summary of the conditions that must be met for constructive and destructive interference:

(Note that for constructive interference, $n = 0$ refers to the case where there is $\textit{zero}$ path length difference, so the two waves naturally arrive in phase. This is the situation for the center yellow dot in Figure 13-11.)