Question

Can someone help with these?

Answer 1

Twelve

For an open ended pipe, the fundamental frequency is dependent on the length of the pipe and the speed of sound.  Slightly less dramatic limiting factors are the temperature and pressure.

In an open pipe column, the fundamental frequency is f1 = V_sound / (2*L) which means that the longer the pipe, the lower the frequency.

Each frequency thereafter is just a multiple of the fundamental frequency.

f2 = 2* f1

f3 = 3 * f1

fn = n*f1

But that is not really what you are being asked. You are asked about the wavelength

Start with the fundamental formula

v = f wavelenght

f = n * v/2L

v = (n*v/2L) * wavelength  The "v"s cancel out

2L / n = wavelength.

Thirteen

Fourteen

If the pipe increases in length, the frequency will go down and the wavelength will go up