Sound waves carry sound energy. The amount of energy emitted by the sound wave from the source per second per unit area is called the intensity of the sound.
The louder the sound has more intensity. The intensity of sound is measured in decibel (dB) units. If anyone cannot hear the intensity of sound between 45 dB and 60 dB, he or she has lost the sensation of hearing partially. The state of not hearing even sound up to 80 dB is called deafness. The high-intensity sound may damage the sensation of hearing.
| Activities of Producing Sound | Intensity of Sound (dB) | Level |
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The intensity of sound at any point is the rate at which sound energy is passing through the unit area perpendicular to the direction of propagation of the sound wave. It is denoted by I and its S.I. unit is W/m² (Watt / square metre). The intensity of sound is measured by using the formula given below.
Calculate the intensity of sound in an area of 5 m² whistling by the children of power 2 × 10⁻⁴ W.
Click a source to see its intensity range and hear a representative tone.