Linked Videos

• Classical electromagnestism. Oscillating electric and magnetic fields.
• Electromagnetic waves have: amplitude, wavelength, frequency
• Sound waves, frequency determined pitch
• Electromagnetic waves frequency corresponds to kinds of light
• Electromagnetic waves, visible light of different wavelengths produce different colors
• Electromagnetic waves, frequencies greater than visible light: ultraviolet, x-ray, gamma
• Electromagnetic waves, frequencies less than visible light: infrared microwave radio
• Electromagnetic radiation, wavelength decreases/frequency increases/energy increases
• All electromagnetic radiation moves at the speed of light
• All waves move at a speed equal to wavelength times frequency
• Electromagnetic radiation has wavelength and frequency
• Electromagnetic radiation, the longer the wavelength the lower the frequency
• Photon is a particle of light
• Electromagnetic radiation, wave particle duality
• The timeline of early modern physics

  • Planck - ultraviolet catastrophe is solved (1901)
  • Einstein - took the next step (1905) with brownian motion, special relativity, the photoelectric effect
  • Bohr - applied quantization to the energy of an electron
• The photoelectric effect, only light above a certain frequency can eject an electron regardless of the beam's intensity
• Light must be made of quanta
• E = hf, an electron is ejected when a photon of sufficient energy strikes the surface
• The energy of the photon depends only on frequency
• Vibrational energy of atoms in a blackbody is quantized, light is also quantized
• Light also exhibits wave-like properties such as diffraction and interference
• Light can behave as both a particle and wave, this is wave particle duality
• Common sense does not apply to the quantum world
• Bohr model, the electron moves between energy levels when a photon is absorbed or emitted
• Quantization of energy for the electron explained emission spectra and the colors of objects
• Louis de Broglie. Matter also exhibits wave particle duality
• Electrons have a wavelength
• Electrons exhibit diffraction
• Waves can act like particles, particles can act like waves
• There are two mathematical relationships we need to understand with light and photons. Fortunately these are very simple equations, and I will of course explain things in terms of relationships as well as simply stating the equations! 
• First, the speed of light (c) is a constant at approximately 3x108 m/s and just like waves that we saw earlier in the course, the speed of a wave is equal to its wavelength (λ) times its frequency (f). v=λf was the equation we used earlier. Now it is simply c=λf.
• Since the speed of light (c) is a constant, it means that for every wavelength there is exactly one frequency, and that those are inversely proportional. As wavelength increases, frequency decreases, and wavelength decreases, frequency increases. In other words, if your speed is constant, you can take many fast small steps or fewer slower big steps to achieve that speed.
• Second, the energy of a photon (E) is proportional to its frequency as a wave (f). The equation that describes this is simply: E=hf=hcλ where the later half is the same as the first half if you substitute the first relationship equation in to this second one. This means that as frequency increases and wave length decreases, the energy of the photon also increases. Or alternatively, lower frequency longer wavelength photons have less energy. 
• We can classify different photons by their frequency (or their wavelength) in to different categories. These categories range from very short wavelengths (very high frequencies) such as gamma rays to very long wave lengths (very low frequencies) such as radio waves. In the middle-ish of all of this is a tiny band of wavelengths that we call visible light. We call it visible because we adapted to see it.
• While colors can be subjective, it is good to set some numerical boundaries for the purpose of communication