Physics Question & Answer Key

Question:

When two organ pipes open at both ends are sounded at their first harmonic, 4 beats/second are heard. One pipe is 1000 mm long. Calculate the length of the other pipe.

Answer:

V = 343 m/s

L₁ = 1000 mm = 1 m

λ = 2L₁ = 2 m

f_beat = ½f₁ – f₂½

4 = (343 / 2) – (343 / l₂)

λ₂ = 2.048

λ₂ = 2L₂

2.048 = 2 L₂

L₂ = 1.024 m = 1024 mm