Ch 05-01 Light and Electromagnetic Waves

• Information carriers (messengers):
  photons (EM waves), cosmic rays, neutrinos, and "gravitons" (GW waves)
   
• The speed of light
  c=299,792,458 m/sec ~ 3 x 10¹⁰ cm/sec
  The constancy of the speed of light in vacuum as measured in all inertial frames.
  (The basic hypothesis of Einstein's Special Relativity.)
   
• The nature of light: electromagnetic waves
  
  
  
   
• Wave-particle duality
  c = νλ
  E = hν          h = 6.63 x 10^-27 erg sec
  
  for λ = 1 cm,       ν = 30 GHz
  for λ = 6000 Å,  ν = 5 x 10¹⁴ Hz,  E = 2 eV
  for λ = 1 Å,    ν = 3 x 10¹⁸ Hz,   E = 12 keV
  1 erg = 0.625 x 10¹² eV