|Class 8 Physics Sound||Characteristics of Sound|
Sound is characterized by 2 important features
Frequency = No of oscillations
Time (in seconds)
If pendulum oscillates 15 times in one minute, the frequency is given by
Frequency = No of oscillations = 15 = 0.5 Hz
Time (in seconds) 30
Frequency determines the shrillness or the pitch of the sound. Higher the frequency, higher the pitch or it is said that the sound is shrilling. Lower the frequency, lower the shrill or pitch. Eg: Babies voice has more frequency and thereby more shrilling than an adult voice.
Loudness = k.(Amplitude)2 (where k is the proportionality constant)
The loudness is expressed in a unit called decibel (dB).
The more the amplitude of vibration, the sound is the loud. The lesser the amplitude of vibration, the sound is feeble.