<p align="right">Last Update: <font color="#4f81bd">January 2, 2025</font></p>
## BIG IDEAS
- The loudness of sound depends on the amplitude of a sound wave.
- Large amplitude has more energy.
- Measured in decibels (dB)
- Sound above 80 dB is noise to the human ear.
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Loudness is measured by the intensity level of a wave (this is not intensity)
### Symbol
$\beta \tag{1}$
### SI Unit
Decibel (dB) --> (Dimensionless)
Formula
$\beta = (10dB) \ log \ (\frac{I}{I_0})$
Where
$I_0 = 10^{-12} \ W/m^2$
### Related Topics
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[[Home|Home]] | [[Oscillations]] | [[Waves]] | [[Module 0 Sound]] | [[Module 1 Sound Waves]] | [[Module 2 Speed of Sound]] | [[Module 3 Sound Intensity]] | [[Module 4 Doppler Effect]] | [[Electromagnetic radiation]]