You sing into a well and find that the well resonates at frequencies of 220 Hz and 260 Hz with no resonances between these two frequencies.
1) What is the frequency of the fundamental mode?
2) What is the depth of the well (Assume the speed of sound is 343 m/s)?
3) Which harmonic is the 220 Hz resonance?
4) Which harmonic is the 260 resonance?