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Why is the speed of light so much faster than the speed of sound?
Question Date: 2004-04-05
Answer 1:

Light and sound travel in waves. They are parts of the electromagnetic and sound spectra.

As you will remember from science class, wave-speed is equal to wavelength multiplied by frequency. White light, or common everyday light, is made up of a mixture of all the colors in the visible spectrum, from red to violet. Therefore, the wavelength of white light(in a vacuum) ranges from 390-780 nanometers (or 10-9 meters!).

The frequency of this light ranges from 769 to 384 terahertz (ask your teacher about the units of frequency).

Depending on the color, the wavelength and frequency change. However, when you multiply one wavelength by its corresponding frequency, you will always end up with the same number:
3*108 meters/second.

The speed of sound is calculated the same way. The frequency of audible sound ranges from around 50 to 15*103 Hz (this varies with different tones, like a tweeter or a woofer. The range of wavelengths is 6.9 m to 2.3 cm. If we multiply these together, we get the same answer, regardless of the tone! We get 344 meters/second.

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