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Question
Two point sources of sound are kept at a separation of 10 cm. They vibrate in phase to produce waves of wavelength 5.0 cm. What would be the phase difference between the two waves arriving at a point 20 cm from one source (a) on the line joining the sources and (b) on the perpendicular bisector of the line joining the sources?
Solution
Given:
Separation between the two point sources ∆x = 10 cm
Wavelength λ = 5.0 cm
(a)
\[\text { Phase difference is given by: }\]
\[ \phi = \frac{2\pi}{\lambda} ∆ x\]
\[So, \]
\[\phi = \frac{2\pi}{5} \times 10 = 4\pi\]
Therefore, the phase difference is zero.
(b) Zero: the particles are in the same phase since they have the same path.
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