Fundamental frequency in a closed pipe

Steps:

• For a pipe closed at one end and open at the other, the lowest (fundamental) frequency has L = λ/4.
• Thus, λ = 4L = 4 × 10 m = 40 m (length adjusted for organ's low note).
• Frequency f = v / λ, with v = 320 m/s.
• f = 320 / 40 = 8 Hz.

Why B is correct:

• The formula f = v/(4L) for a closed pipe's fundamental mode gives 8 Hz when L = 10 m, matching the low tone produced.

Why the others are wrong:

• A: 4 Hz requires L = 20 m, longer than given.
• C: 16 Hz requires L = 5 m, half the effective length.
• D: 32 Hz requires L = 2.5 m, quarter of the effective length.

Final answer: B