ASTR 1345 1st Edition Lecture 12 Outline of Last Lecture I. Electromagnetic Waves/SpectrumII. Wave QuantitiesA. SpeedB. WavelengthC. FrequencyIII. Properties of LightA. ReflectionB. RefractionC. DispersionIV. Light Waves and Finite Speed of LightV. PhotonsVI. Colors and FrequencyOutline of Current Lecture I. More Properties of Light A. PolarizationB. Diffraction1. Diffraction GratingC. Interference 2. Constructive Interference3. Destructive Interference II. Why the Sky is BlueIII. Transparency of Earth’s AtmosphereCurrent Lecturel.A. Polarization is the restriction of vibration of (transverse) wave to a particular direction.B. Diffraction is the bending of a light or wave behind an aperture or around an obstacle.1. Diffraction grating consists of thousands of equally spaced fine lines ruled on a small rectangular plastic slide, used to give sharp interference maxima.C. Interference is the combo of two or more waves of the same type and wavelength whichmeet at a point in space.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.2. Constructive interference occurs when 2 waves are in phase, so the crests coincide.3. Destructive interference occurs when 2 waves are 90 degrees out of phase, so the crest of 1 wave coincides with the trough of the other.ll.The Sky is blue because sunlight contains all colors of the rainbow. Molecules of Earth’s atmosphere scatter incoming molecules in all directions. Blue (short wavelength) end of spectrum is scattered more than red (long wavelength) end. At sunrise or sunset the sun’s rays take a longer path through the atmosphere so more sunlight is scattered making the sun appearorange or red.lll.Only visible light and radio waves reach the ground at all their wavelengths, while all infrared rays reach high mountains. Some UV rays get through, but most is blocked by the ozone layer. No X Rays or Gamma Rays get through because of Earth’s
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