How to Find Photon Frequency
- 1). Obtain the physical constant values needed for the calculation of the 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). Become familiar with metric prefixes normally used to represent either very big numbers (such as photon frequencies) or very small (such as wavelengths). Prefixes used in this examples are:
"Tera (T)-" means the magnitude of 1E12.
"Nano (n)-" means the magnitude of 1E-9. - 3). Divide the speed of light by the wavelength to calculate the photon frequency. For example, calculate the photon frequency of the blue light with the wavelength of 450 nanometers (nm):
Frequency = 299,792,458 (m/s) / 450 E-9 m = 6.66 E14 Hz = 666 E12 Hz = 666 THz. Note that 450 nm = 450 E-9 m due to the prefix "nano." - 4). Divide the photon energy by the Planck constant to calculate the frequency. For example, if the photon energy is 2.15 electron volt (eV), then
the frequency is 2.15 eV / 4.13566733E'15 eV s = 5.20 E14 Hz = 520 E12 = 520 THz.