<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. --- 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 --- [[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]]