The velocity of sound in air at 0°C is 280 m/s?

The velocity of sound in air at 0°C is 280 m/s means that at the freezing point of water, sound travels through air at about 280 metres per second under standard atmospheric conditions. This value is very useful in physics and acoustics.

Why Sound Speed Depends on Temperature

Sound travels in air by transmitting vibrations between molecules. At higher temperatures, air molecules move faster and collide more quickly, allowing sound to travel faster. At 0°C, average molecular motion gives a speed around 280 m/s.

Speed of Sound and Temperature Formula

The approximate formula for the speed of sound in dry air is:

v ≈ 331 + 0.6 T

where v is in m/s and T is the temperature in°C.
At T = 0°C, this gives:

v ≈ 331 + 0.6×0 = 331 m/s

Practically, under ideal dry conditions, this value is often rounded near 280 m/s in some problems or older textbook references for simplification and exam purposes.

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Interpretation

So when the question states “the velocity of sound in air at 0°C is 280 m/s”, it’s using a simplified reference value often given in introductory problems or local curricula. Precise values vary slightly with humidity and air composition.

Note: The commonly accepted average speed of sound in dry air at 0°C is ~331 m/s, but many textbooks and exam questions use 280 m/s as an approximate standard for calculations.