frequency question?

Question

a flute open at both ends and an organ pipe closed at one end have the same length
organ pipe has a fundamental frequency of 130hz
what is the flutes fundamental frequency and what assumptions are we making

Answer 1

Flute, assuming it's open at both ends, is 0.5 wavelength long. The closed organ pipe is 0.25 wavelength long. From this you can get that the flute's frequency is double the organ pipe's. Other assumptions are that the ratio of pipe diameter to length is small; otherwise the formula loses accuracy. See ref.