Two coherent sources of sound, S_1 and S_2, produce sound waves of the same wavelength, λ=1 m, in phase. S_1 and S_2 are placed 1.5 m apart (see…

Two coherent sources of sound, $\displaystyle \mathrm{S}_1$ and $\displaystyle \mathrm{S}_2$, produce sound waves of the same wavelength, $\displaystyle \lambda=1 \mathrm{~m}$, in phase. $\displaystyle \mathrm{S}_1$ and $\displaystyle \mathrm{S}_2$ are placed $\displaystyle 1.5$ m apart (see fig). A listener, located at L, directly in front of $\displaystyle \mathrm{S}_2$ finds that the intensity is at a minimum when he is $\displaystyle 2$ m away from $\displaystyle \mathrm{S}_2$. The listener moves away from $\displaystyle \mathrm{S}_1$, keeping his distance from $\displaystyle \mathrm{S}_2$ fixed. The adjacent maximum of intensity is observed when the listener is at a distance $\displaystyle d$ from $\displaystyle S_1$. Then, $\displaystyle d$ is :