Wednesday 26 July 2017

Term 3 Week 1 2017

Homework:

  • Ex 3D, p. 75-79 Standing Waves and Music
  • Ex 3E, p. 81-84 Beats

Standing Waves


in musical instruments - when a reflected wave travels back through itself causing fixed points of Nodes (Deconstructive Interference) and Antinodes (Constructive Interference) due to the fractional relationship between the wavelength (𝜆) of the wave and the length (L) of the resonating chamber



Harmonic
String
Double Open Ended Pipe
Closed Ended Pipe
1st
𝜆 = 2L
f = f1st
𝜆 = 2L
f = f1st
𝜆 = 4L
f = f1st
2nd
𝜆 = L
f = 2f1st
𝜆 = L
f = 2f1st

3rd
𝜆 = ⅔ L
f = 3f1st
𝜆 = ⅔ L
f = 3f1st
𝜆 = 4/3 L
f = 3f1st
4th
𝜆 = ½ L
f = 4f1st
𝜆 = ½ L
f = 4f1st

5th
𝜆 = ⅖ L
f = 5f1st
𝜆 = ⅖ L
f = 5f1st
𝜆 = ⅘ L
f = 5f1st




Standing Waves Part I: Demonstration


Standing Waves Part II: Explanation

Standing Waves

Making standing waves

Singing plates - Standing Waves on Chladni plates



Acoustic Levitation in ULTRA SLOW MOTION


Beats


two waves of a similar frequency (similar wavelength) superimpose to come in and out of phase causing constructive and deconstructive interference respectively. This causes a warbling/beat sound of frequency (fb) equal to the difference in respective frequencies

fb = | f1 - f2 |

Wave Beats

Easy Beats- Physics


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