Light, photons, and oscillating electromagnetic fields explained.

This video explains the particle nature of light, its connection to electric and magnetic field oscillations, their connection to frequency, wavelength, and to the energy of a photon.

 

  • KEY CONCEPT: Light produces both an electric field and a magnetic field

  • What is a Photon? 

    • Electric field oscillations connect photons to waves and gives ​frequency and wavelength, as well as magnetic field oscillations and the energy measurement of the photon

      • Combining all this gives us electromagnetic ​radiation! 

        • Electromagnetic radiation is LIGHT!

  • Depending on how you measure light, it may act like a wave or act like a particle

  • The word "photon" represents the particle natrure of light 

  • There is also an electric field that we can portray as a constantly oscillating vector above and below the photon 

    • Because of these oscillations, light is also generating a wave​, which gives light its wave character (which we can portray as a trace)

      • But the wave only really exists where it is being generated by the oscillating field ​

  • A pure color is a single wavelength of light with a.specific frequency 

    • i.e. a red laser emits 650 nm, a green laser at 532 nm​

      • The green oscillates more frequently per unit time --> has a higher frequency = shorter wavelengt

      • The pure red light of most red laser pointers oscillates at 4.6 x 10^14 oscillations per second 

        • 4.6 x 10^14 Hertz =

        • 4.6 x 10^14 cycles per second =

        • the frequency ​

  • There is a direct mathematical relationship between the number of electric field oscillations and the photon's energy

    • The energy of a single photon is the number of electric field oscillations and the photon's energy​

      • Through math, we can see that the green light has a higher energy that red, corresponding exactly to the number of oscillations

  • Any moving electric field produces a perpendicular magnetic field 

  • This is why light is called electro-magnetic radiation! 

    • The fact that light produces both an electric field and a magnetic field was originally deduced by physicist James Maxwell in 1868. ​