Resonant Frequencies Of Closed Organ Pipes — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Resonant Frequencies of Closed Organ Pipes Applies to cylindrical pipes open at one end and closed at the other, assuming the pipe diameter is negligible compared to length (no end correction applied). Assume a displacement node at the closed end and an antinode at the open end. The length L is equal to odd multiples of quarter wavelengths: L = n(lambda/4) for n=1,3,5... Substitute lambda = v/f into the length equation. Solve for f. n must be an odd integer (1, 3, 5...) L > 0 v > 0 Using n as even integers (closed pipes only produce odd harmonics). Using 2L in the denominator (formula for open pipes) instead of 4L. Confusing the 3rd harmonic (n=3) with the '2nd resonant mode' (which is actually the 1st overtone).