At what frequency / wavelength does a soundwave increase from"speed of sound" to "speed of light".

Question

At what frequency / wavelength does a soundwave increase from"speed of sound" to "speed of light".

Answer 1

the speed of sound in air is around 300m/s but air is very elastic.  In a more rigid substance like water or moreso steel, sound travels at much higher speeds but still not at the speed of light which is 300,000km/s.  The speed of sound in any medium is only a function of the properties of the medium and not of frequency or wavelength.

If sound waves (pressure waves) transfer from air to steel they will stay at the same frequency but (because of the much higher speed in steel) their wavelength will become proportionately much longer.

Answer 2

A sound wave will never go faster than the speed of sound. by definition.

You are getting confused between sound waves, which travel at the speed of sound, and electro-magnetic radiation that travels at the speed of light.

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