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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