Answer: 340 Hz.
- A 170 Hz
- B 340 Hz
- C 680 Hz
- D 85 Hz
Correct answer: B. 340 Hz
Explanation: Open pipe: f<sub>1</sub> = v/(2L) = 340/(2 x 0.5) = 340 Hz.
A standing wave forms from two identical waves travelling in opposite directions and interfering; nodes (always zero displacement) and antinodes (maximum displacement) stay fixed in place, unlike a travelling wave where the whole pattern moves.
Concept context
Wave types, superposition, standing waves, Doppler effect, and sound intensity.