How to Calculate Frequency of a Photon of Light
- 1). Note the fundamental physical constants needed for frequency calculations:
Speed of light (c) = 299,792,458 m/s;
Planck constant (h) = 4.13566733E'15 eV s (1E-15 denotes "ten in power -15"). - 2). Divide the speed of light by the wavelength to calculate the frequency of the light.
Frequency (Hz) = c/ wavelength = 299,792,458 / wavelength.
As example, calculate the frequency of the green light with the wavelength of 510 nanometers (nm); 510 nm = 5.1E-7 m.
Frequency = 299,792,458 (m/s) / 5.1E-7 m = 5.88E14 Hz = 588 THz. Note the prefix "Tera(T)-" implies the magnitude of 1E12. - 3). Divide the photon energy by the Planck constant to calculate the frequency of the light:
Frequency(Hz) = Energy/h = Energy/4.13566733E'15 eV s.
For example, if the photon energy is 3.7 electron volt (eV) then
the frequency is 3.7 eV / 4.13566733E'15 eV s = 8.94E14 Hz = 894 THz.
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