The to and fro motion is called oscillatory motion.
Sound travels in the form of a wave. So it has the same three important characteristics as wave.
Amplitude:
The maximum displacement of the object from the mean position during oscillation is called the amplitude of the oscillation.
Time Period:
The time taken to complete one oscillation is called the time period of the oscillation.
Its unit is seconds.
Frequency:
The number of oscillations per second is called the frequency of oscillations.
Its unit is Hertz. Its symbol is Hz.
A frequency of 1 hertz is one oscillation per second.
Two important characteristics of sound are
Amplitude and loudness:
The amplitude of the vibrating body producing the sound determines the loudness of the sound.
Loudness of sound is proportional to the square of the amplitude of the vibration producing the sound. For example, if the amplitude becomes twice, the loudness increases by a factor of 4.
If the amplitude is higher, the sound produced is louder.
If the amplitude is lower, the sound produced is feeble or slower.
The loudness is expressed in a unit called decibel (dB)
Frequency and pitch:
The Frequency determines the shrillness or pitch of a sound.
If the frequency of vibration is higher then the sound is shrill and has a higher pitch.
If the Frequency of Vibration is lower, sound is deep or has lower pitch.
