Edexcel A Level Physics:复习笔记5.33 Energy of a Photon

• Photons are fundamental particles which make up all forms of electromagnetic radiation
• A photon is a massless “packet” or a “quantum” of electromagnetic energy
• What this means is that the energy is not transferred continuously, but as discrete packets of energy
• In other words, each photon carries a specific amount of energy, and transfers this energy all in one go, rather than supplying a consistent amount of energy

Calculating Photon Energy

• The energy of a photon can be calculated using the formula:

• Using the wave equation, energy can also be equal to:

• Where:
  • E = energy of the photon (J)
  • h = Planck's constant (J s)
  • c = the speed of light (m s-1)
  • f = frequency (Hz)
  • λ = wavelength (m)

   

• This equation tells us:
  • The higher the frequency of EM radiation, the higher the energy of the photon
  • The energy of a photon is inversely proportional to the wavelength
  • A long-wavelength photon of light has a lower energy than a shorter-wavelength photon