CH7 Waves and Sound

Question 1

• Propagation Speed (v) of a wave
• what is frequency and wavelength
• Period Equation
• Angular frequency

Answer 1

• v = f x wavelength
• wavelength = distance from one maximum crest to the next
• f = 1 / s ( # of wavelenghts passing a fixed point per s)
• T = 1/f
• Angular f = 2 pi f = 2 pi / T

Question 2

The doppler effect equation

Answer 2

Question 3

Intensity and Loudness

decibels equation

threshold of hearing, pain, and eardrum perforation

Answer 3

• Loudness of a sound is our mental and physiological perception of its intensity
• I = P / A

Intensity = W / m²

• dB = 10 log (I/I₀)

I0 = threshold of hearing (1 x 10^-12)

• Pain: 130 dB or 10¹
• Perforation: 160 dB or 10⁴

Question 4

Nodes are places of no displacement

shortcuts for finding the length/wavelenghts of a wave in string attached, open tubes,

Answer 4

L = (wavelengths x n) / 2

Strings attached: n = # of antinodes

Open pipies: # of nodes