Things You'll Need
Instructions
Retrieve the Planck constant value: 6.626 069 57 x10^-34 J s.
Get the speed of light constant: 299,792,458 m/s.
Multiply the Planck constant by the speed of light: 6.62606957 x10^-34 J s x 299,792,458 m/s = 1,98645 x10^-25 J m.
Divide the wavelength in nanometers by 10^-9 to calculate the value in meters. For example, the wavelength of 500 nm corresponds to 500/10^-9 = 5x10^-7 meters (m).
Divide the product of the constants by the wavelength in meters to calculate the energy in Joules. In this example, the energy is 1,98645 x10^-25 J m / 5x10^-7 m = 3.973 x10-19 J.