Physics Help Forum Energy proportional to wave amplitude squared ? for 2D wave

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 Jun 3rd 2018, 04:58 AM #1 Junior Member   Join Date: May 2018 Posts: 11 Energy proportional to wave amplitude squared ? for 2D wave My textbook says that the energy of a wave is proportional to the square of the wave amplitude. They derived this for a 3 dimensional wave moving out in a sphere. They then apply the same relationship to a ripple moving across a pond ( a 2D wave). Is the same relationship valid?
Jun 3rd 2018, 05:37 AM   #2
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 Originally Posted by justme My textbook says that the energy of a wave is proportional to the square of the wave amplitude. They derived this for a 3 dimensional wave moving out in a sphere. They then apply the same relationship to a ripple moving across a pond ( a 2D wave). Is the same relationship valid?
Yes, it is true of all waves.

You should also distinguish between the energy and energy density of a wave.

It is the energy density which changes as the wave spreads out. (but not all waves spread out)

 Tags amplitude, energy, proportional, squared, wave

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