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⚛️ Physics  ·  Waves  ·  NEET & JEE

Speed of sound in air increases with temperature. At 0°C it is 332 m/s. At 20°C approximate speed is:

Answer: 343 m/s.

  • A 332 m/s
  • B 340 m/s
  • C 343 m/s
  • D 350 m/s

Correct answer: C. 343 m/s

Explanation: v increases by about 0.6 m/s per degree Celsius. At 20°C: v = 332 + 0.6 x 20 = 344 m/s, approximately 343 m/s.

Standing Wave: Nodes and Antinodes (Open Pipe, 2nd Harmonic)nodenodenodeantinodeantinodeSolid and dashed lines show the string/air column at two instants - nodes never move

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.

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