Find the fundamental, first overtone and second overtone frequencies of an open organ pipe of length 20 cm. Speed of sound in air is 340ms−1.
850 Hz, 1750 Hz, 2550 Hz
Fundamental frequency First overtone
λ2 = L 2(λ2) = L
λ = 2L f = vL
λ f = v vf = 2L
f = v2L
If V = 340ms,L = 20 cm = 20 × 10−2m
Fundamental frequency =V2L = 3402 × 20 × 10−2 = 850 Hz
we know first overstone =2V2L = 2 × 3402 × 20 × 10−2 (for open pipe) = 1750 Hz
Second overtone =3(V2L) = 3 × 850 = 2550