- #1
Daker
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Hi
There is something wrong with this logic. Anyone see the flaw.
If we have a wave in y traveling along the z axis y= y_0cos(kz-wt) then the energy it carries is proportional to y_0^2. If we superimpose a second wave with the same amplitude (and so the same energy) and in phase with the first wave then we add the amplitudes to get a wave described by y= 2y0cos(kz-wt). The energy in this wave is proportional to the amplitude squared i.e. 4y_0^2. But energy is not conserved between the two initial waves and the resultant wave i.e y_0^2+y_0^2 \ne 4y_0^2.
Similarly if the waves are pi out of phase the resultant is zero and in this case y_0^2+y_0^2 = 0!
Sorry for being dumb!
Daker
There is something wrong with this logic. Anyone see the flaw.
If we have a wave in y traveling along the z axis y= y_0cos(kz-wt) then the energy it carries is proportional to y_0^2. If we superimpose a second wave with the same amplitude (and so the same energy) and in phase with the first wave then we add the amplitudes to get a wave described by y= 2y0cos(kz-wt). The energy in this wave is proportional to the amplitude squared i.e. 4y_0^2. But energy is not conserved between the two initial waves and the resultant wave i.e y_0^2+y_0^2 \ne 4y_0^2.
Similarly if the waves are pi out of phase the resultant is zero and in this case y_0^2+y_0^2 = 0!
Sorry for being dumb!
Daker