Waves

1st Harmonic - 20Hz - F₀ - wavelength 2L
2nd Harmonic - 40Hz - 2F₀ - wavelength L
3rd Harmonic - 60Hz - 3F₀ - wavelength 2/3L

Can someone explain this how does the frequency relate to the wavelength as the harmonic increases?

If the Length of the string is L how does frequency effect this? How do you work out the wavelength?

The equation to remember is:

wavelength / 2 = L

So if we have 3 fll wavlengths in the tube (standing waves), then it becomes:

3wavelengths / 2 = L
Rearrange to get wavlength:

Wavelength = 2L/3

HIgher harmonic means more wavelengths in the same tube/length, so the frequence will increase as there are more per unit time/length.

So: wavelength decreases as frequence increases.

Is this the seperation between the adjacent nodes?

Secondly how do workout how many waves there are? So for the 3rd harmonic there is 3 wavelengths?

The seperation is between adjacent nodes or antinodes.

For the second question, do you mean how many ful wavenlengths, because there is 1 standing wave, but 1.5 wavlengths. Im assuming you got 3 which is the number of full circles? Remember that one full circle is only half a wavelength, so 3 full circles = 3/2 wavelengths.

Yes i mean full wavelength how are you getting 3 wavelengths? Yh i dont understand the working behind that

Think I've confused myself, which harmonic are we looking at?

3rd harmonic has 4nodes and 3 Antinodes

The way I do it, I just look at the whole number of circles which in this case is 3 and divide it by 2 since each one it half a wavlength, sorry about the confusion

3rd harmonic has 4nodes and 3 Antinodes
So one wavelength is 3/2 right

For the 4th harmonic one wavelength is 1/2

but for the 5th how many is one wavelength? How do you work this out

I thought you only need to know up to the 3rd harmonic. Also, I think it depends on if its an open ended or close ended tube

well its say the L is 2/5L