First determine the wavelength of light. Any equipment not required for this - to know this value with sufficient accuracy, it is possible for eyes. Red light has a wavelength of from 650 to 690 nm, red-orange, about 620, orange - from 590 to 600, yellow, from 570 to 580, green is about 550, emerald - from 500 to 520, a blue - 450 to 480, violet from 420 to 390. However, if the experiment is carried out in a physics lab to determine the wavelength of light more accurately using a special instrument, spectrometer.
For convenience, set the wavelength of the light in meters. One nanometer is 10^(-9) meters. Use the scientific calculator as usual to work with numbers in this range are not capable.
You now have enough information to calculate the frequency of light in Hertz. The second value you want to use in calculations is the speed of light. She is 299792458 meters per second. Divide this value by the wavelength -, and frequency.
Now, for convenience, set the received frequency in terahertz. One terahertz is 10^12 Hz. The result should be in the range from 400 to 800 terahertz. Note that frequency is inversely proportional to the wavelength, so red light corresponds to the lower limit of this range, and purple - top.
Similarly, you can define frequency wavelength and Vice versa in relation to other types of radiation. Radio waves have frequencies from hundreds of kilohertz to tens of gigahertz, and wavelengths from a few millimeters to hundreds of meters. If the radiation is not electromagnetic (for example, we are talking about sound, ultrasound), note that it propagates much slower than light. In addition, the speed of sound is much larger than the speed of lightdepends on the medium in which the radiation propagates.