Answer: 250 Hz.
- A 200 Hz
- B 250 Hz
- C 400 Hz
- D 500 Hz
Correct answer: B. 250 Hz
Explanation: String fixed at both ends: f<sub>1</sub> = v/(2L) = 400/(2 x 0.8) = 400/1.6 = 250 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.