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# Standing waves-Physics watch

1. A loudspeaker points directly at a wall 3m away. It emits a wave of frequency 680Hz and a standing wave is formed.

Is this the correct way to work this out?

v=fλ

340/680=λ

λ=1/2

λ=2L - I'm assuming this is the frist harmonic, even though it doesnt state. Is this normal?

L=0.5/2

L=0.25
2. If it is first harmonic, the length of the string is 2 times the wavelength. Therefore L = 2λ, L/2 = λ. Now sub in ya values so L = ?.
3. (Original post by assassinjeev22)
If it is first harmonic, the length of the string is 2 times the wavelength. Therefore L = 2λ, L/2 = λ. Now sub in ya values so L = ?.
shouldn't it be λ=2L and L=λ/2
4. (Original post by joyoustele)
shouldn't it be λ=2L and L=λ/2
Oh yeah sorry got abit muddled up there my apologies

Other than that yeah all seems good but they usually do state if its first harmonic(aka fundamental frequency), 2nd harmonic etc.

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