Themes > Science > Chemistry > General Chemistry > Atomic Structure > Electronic Structures of Atoms > Atomic Structure Index > Photon Energy

Although light behaves like a wave, having both a wavelength and a frequency, a series of experiments by Planck and Einstein in the early 1900s showed that it also exhibits particle-like behavior. These light particles are called photons, and the energy of a given particle of light can be computed from the simple relationship
E = hn
where h is Planck's constant, 6.626*10-34J*s and n is the frequency of the light. Using the wave relation n = c/l, the above equation can also be written as
E = hc/l
Note that high energy light has a large frequency and a small wavelength

Example: What is the energy of a photon with frequency 1.35*107 1/s?

Solution: Simply use the relationship between the frequency and energy of a photon

E = hn
E = 6.626*10-34J*s * 1.35*107 1/s
E = 8.95*10-27 J
An individual light photon has very little energy.


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