frequency is the speed of vibration and this determines the pitch of the sound. it is only useful or meaningful for musical sounds. where there is a strongly regular waveform. frequency is measured as the number of wave cycles that occur in one second. the unit that is being measured is (hz)
As you run toward a source of sound, you perceive the frequency of that sound to decrease.
Explanation:
Doppler's effect is a principle used to describe the frequency and the intensity of sound and wavelengths of a source and observer with the two possibilities.
(i) Stationary sound source and moving observer.
(ii) Moving sound source and a stationary observer. It is a relative motion.
Consider when the observer is moving towards a source, the frequency of the sound will be higher and when moving away from the source, the frequency will decrease.
