In a classroom experiment the centres of successive compressions of a sound wave travelling in air are made visible by a row of light pith balls hanging from threads. The distance between the first and the seventh compression along the line of propagation is measured to be 1.02m.
(i) How many complete wavelengths are contained between these two compressions?
(ii) Calculate the wavelength of the sound wave.
(iii) If the speed of sound in air is 340m/s, determine the frequency of this wave.
(iv) State whether this frequency lies within the normal audible range of human hearing and justify your answer briefly.