Question

1. When a sound wave passes through air, and we hear it, the air pressure where we are varies with time. the excess pressure above (and below) atmospheric pressure in a sound wave is given by the graph below: p(t) t in seconds -1 (a) Show that the fundamental (n ) is 15 times smaller in amplitude compared to the second harmonic (n-2). Hint: Expand p() in a Fourier series to show this. It would be interesting to note that the fundamental frequency corresponds approximately to middle Con a piano. (b) What frequencies do you hear when you listen to such a sound wave? Hint: Assume that the intensity of the sound wave (average energy striking unit area of your ear per second) is proportional to the average of the square of the excess pressure.

Answer 1

0) Fust ne en Per seand we have Caled te enod 1 im or mau.」 S24 124 o 48 1048 7 hn vn!,.( mh-vt λ, 연 (yw.fde tr'm-Hun w. Czu Values n) uati eta