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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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Chapter 4 The Nature or Light and Matter Survey of Astronomy astro1010-lee.com twlee2016@gmail.com
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
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
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
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
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
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
Chapter 4 Wien’s Law [The hotter the bluer] Survey of Astronomy astro1010-lee.com twlee2016@gmail.com
Chapter 4 Stefan-Boltzmann Law [The hotter the brighter] Survey of Astronomy astro1010-lee.com twlee2016@gmail.com
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
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
Chapter 4 Non-Thermal Radiation Survey of Astronomy astro1010-lee.com twlee2016@gmail.com
Chapter 4 Hydrogen Emission Lines Survey of Astronomy astro1010-lee.com twlee2016@gmail.com
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
Chapter 4 Photon Emission Survey of Astronomy astro1010-lee.com twlee2016@gmail.com
Chapter 4 Photon Absorption Survey of Astronomy astro1010-lee.com twlee2016@gmail.com
Chapter 4 Hydrogen Absorption Lines Survey of Astronomy astro1010-lee.com twlee2016@gmail.com
Chapter 4 Kirchhoff’s Laws Survey of Astronomy astro1010-lee.com twlee2016@gmail.com
Chapter 4 Kirchhoff’s Laws (Schematic) Survey of Astronomy astro1010-lee.com twlee2016@gmail.com
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
Chapter Four Chapter 4 Doppler Effect Survey of Astronomy astro1010-lee.com twlee2016@gmail.com
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
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
Chapter 4 End of Chapter 4 Survey of Astronomy astro1010-lee.com twlee2016@gmail.com