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The Nature or Light and Matter

Chapter 4. The Nature or Light and Matter. Survey of Astronomy. astro1010-lee.com. twlee2016@gmail.com. Chapter 4. Measuring the Velocity of Light.

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The Nature or Light and Matter

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  1. Chapter 4 The Nature or Light and Matter Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  2. Chapter 4 Measuring the Velocity of Light Distance is the measured path from the light source, to the rotating mirror, to the stationary mirror, back to the rotating mirror and to the observer. Time is the time it takes for the spinning mirror to turn between reflecting angles. The velocity of light = C = D/T = 300,000 km/sec Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  3. Chapter 4 The Wave Nature of Light Refraction Survey of Astronomy astro1010-lee.com Refraction is a property of a wave that causes it to change direction as it passes through a different medium. The longer wavelengths are bent the least, the short are bent the most. twlee2016@gmail.com

  4. Chapter 4 The Wave Nature of Light Diffraction Survey of Astronomy astro1010-lee.com Diffraction allows the waves to interact with each other, sometimes cancelling and sometime reinforcing. twlee2016@gmail.com

  5. Chapter 4 The Wave Nature of Light Electromagnetic Wave Survey of Astronomy astro1010-lee.com Visible light is part of an electromagnetic spectrum whose waves travel at the velocity of light. All parts of the spectrum have in common that their waves have both a magnetic and an electric component. twlee2016@gmail.com

  6. Chapter 4 Electro-magnetic Spectrum There is no limit to the wavelengths of the electro-magnetic waves from the very short gamma waves to the very long radio waves. The various sections of the spectrum have different names but they have many features in common. Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  7. Chapter 4 Thermal Curves When solids, liquids or gas at high pressure are heated to incandescence and viewed with at spectrograph the results are Continuous Curves of a characteristic shape. These results are also known as Black Body Curves or Thermal Curves Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  8. Chapter 4 Wien’s Law [The hotter the bluer] Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  9. Chapter 4 Stefan-Boltzmann Law [The hotter the brighter] Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  10. Chapter 4 Particle Nature of Light Einstein described the second nature of light as a bundle of energy (photon) which was inversely proportional to the wavelength, Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  11. Chapter 4 Non-Thermal Radiation Spectral lines are images of the entrance slit on the photo plate in each of the colors contained in the original light. Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  12. Chapter 4 Non-Thermal Radiation Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  13. Chapter 4 Hydrogen Emission Lines Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  14. Chapter 4 Bohr Model of an Atom The Niels Bohr model of the atom was a major leap forward in our understanding of atomic structure, but it was not the final answer. Bohr postulated that electron orbits about the nucleus are quantized. Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  15. Chapter 4 Photon Emission Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  16. Chapter 4 Photon Absorption Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  17. Chapter 4 Hydrogen Absorption Lines Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  18. Chapter 4 Kirchhoff’s Laws Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  19. Chapter 4 Kirchhoff’s Laws (Schematic) Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  20. Chapter 4 Light and Matter • Photons • Produced and absorbed by electron transitions • Transitions • Movement of electrons between energy levels • Energy levels • Stable values of energies for electrons • Excitation • When an electron is in any level except the ground state • By collisions between atoms or by absorption of photons Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  21. Chapter Four Chapter 4 Doppler Effect Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  22. Chapter 4 Doppler Effect Original Doppler Experiment Survey of Astronomy astro1010-lee.com Doppler used friends with ‘perfect pitch’ to make the measurements. twlee2016@gmail.com

  23. Chapter 4 Doppler Effect Doppler Equation Survey of Astronomy astro1010-lee.com It must be remembered that this equation only measures ‘line of sight’ velocity twlee2016@gmail.com

  24. Chapter 4 In Class Quiz A cool gas in front of a blackbody source produces an ___________ line spectrum Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

  25. Chapter 4 End of Chapter 4 Survey of Astronomy astro1010-lee.com twlee2016@gmail.com

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