Physics Q Pack #7

[deleted647690]

I'm confused as to how they determined which wave corresponded to which harmonic. I assumed the wave with the largest wavelength (solid line) was the 3rd harmonic, because from looking at graphs 1B and 1C, it looks like the peak amplitudes (both positive and negative amplitude peaks) got larger. The solid line looks like it has the largest amplitude out of the three, so I assumed the addition of the solid one formed the composite wave seen in 1C, thus the solid one was the 3rd harmonic. However, according to the answer to question 7, this is not the case.

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[JustinM88]

maybe these two pics will help?

 

[deleted647690]

maybe these two pics will help?

Oh so each successive harmonic has a smaller wavelength? I guess I didn't understand what a harmonic is. But wouldn't their first harmonic technically have one antinode? Or I guess if you zoomed out to the point where it had 2 antinodes, as shown in their picture? I think I'm just lost on what exactly harmonics for standing waves are...

 

[JustinM88]

Oh so each successive harmonic has a smaller wavelength? I guess I didn't understand what a harmonic is. But wouldn't their first harmonic technically have one antinode? Or I guess if you zoomed out to the point where it had 2 antinodes, as shown in their picture? I think I'm just lost on what exactly harmonics for standing waves are...

yeah if you zoomed out to the point where you see one complete wave it may make more sense. I don't think you need to think in terms of antinodes really for this question

One wavelength would be like this (up down back up again):


When looking at that first picture I posted up there, you could "zoom out" on the 1st harmonic to eventually see the whole wavelength