A loudspeaker vibrates with frequency f and produces sound waves of wavelength \lambda. The loudspeaker completes N oscillations in time t. State expressions, in terms of some or all of the symbols f, \lambda and N, for: (1) the distance travelled by a wavefront in time t, and (2) the time t.
Use your answers in part (a)(i) to deduce the equation that links the speed v of the sound wave with f and \lambda.
The waveform of a sound wave is shown on the screen of a cathode-ray oscilloscope (c.r.o.), as in Fig. 5.1. The time-base setting is 0.20\,\text{ms cm}^{-1}. Determine the frequency of the sound wave.
Two sources S_1 and S_2 of sound waves are arranged as shown in Fig. 5.2. The sources emit coherent sound waves of wavelength 0.85\,\text{m}. Explain what is meant by coherent waves.
State the phase difference between the two waves reaching the minimum-loudness point Q that is nearest to point X.
Distance S_1X equals distance S_2X. Distance S_2Y is 7.40\,\text{m}. Determine the distance S_1Y.