A narrow sound pulse (for example, a short pip by a whistle) is sent across a medium (a) Does the pulse have a definite (i) frequency (ii) wavelength (iii) speed of propagation? (b) If the pulse rate is 1 after every 20s. (that is the whistle is blown for a split of second after every 20s), is the frequency of the note produced by the whistle equal to 1/20 or 0.05Hz?

Explanation

(a) A very short (narrow) sound pulse does not have definite wavelength or frequency because for having definite wavelength or frequency we should produce harmonic type disturbance in the medium for little long time.
But above pulse definitely has its definite speed of propagation in a non dispersive medium.
(b) Here `(1)/(20)` Hz is the frequency of production of pulse. It is not the frequency of wave, because here production of pulse is not continuous.