Answer: 343 m/s.
- A 300 m/s
- B 343 m/s
- C 1500 m/s
- D 3 x 10<sup>8</sup> m/s
Correct answer: B. 343 m/s
Explanation: Speed of sound in air at 20°C is approximately 343 m/s.
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.