Wavelength Distance between two successive condensations or rarefactions. Distance between successive identical points in the waveform. 1

Other terms Pressure = Force/Area; Unit: Newton/meter2 , dyne/centimeter2 or Pascal (Pa) Energy = Ability to do work; Unit: Joule Power = Energy/Time; Unit: Joule/Second or watt 2

Sound intensity in terms of power Amount of energy transmitted per second over an area of one square meter Unit: watt/meter2 or w/m2 3

Normal human hearing in terms of power Least amount of sound power that can be detected: 10-12 w/m2 or 10-16 w/cm2 Sounds that are damaging to the ear: 102 w/m2 or 10-2 w/cm2 4

Bel and Decibel 1 Bel = 10 Decibels Logarithmic units of sound intensity Bel = log (I1/I0) Decibel = one-tenth of a Bel, i.e. 1 Bel = 10 Decibels 5

Rules of exponents Xn = X x X x X …….n times X-n = 1/ Xn X0 = 1 6

Laws of Exponents Xa x Xb = X a+b Xa/Xb = X a-b ( Xa)b = Xab 7

Logarithm Question: To what power must a known base be raised to obtain a certain value? 2? = 8 23 = 8 is the same as Log28 = 3 8

Laws of Logarithms log a * b = log a + log b log a/b = log a – log b log (a)b = b * (log a) log 1/a = - log a 9

log 10 = 1 log 2 = 0.3010 log 3 = 0.48 log 7 = 0.85 10