Answer: 550 Hz.
- A 450 Hz
- B 500 Hz
- C 550 Hz
- D 600 Hz
Correct answer: C. 550 Hz
Explanation: f<sub>obs</sub> = f(v + v<sub>o</sub>)/v = 500 x (340+34)/340 = 500 x 374/340 = 550 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.