©1990-2002 J.Paul Robinson, Purdue University
 
  
  
  
  
  
  
  
  
  
 
  
  
  
 
  
  
 
  
  
  
 
  
  
  
 
 The light spectrum
 •Wavelength =  Frequency
 
 Blue
 light
 488
 nm
 short
 wavelength
 high frequency
 high
 energy (2 times the
 red)
  
 
 Red light
 650
 nm
 long
 wavelength
 low frequency
 low energy
  
 
  
   
   
   
  
   
   
   
  
  
   
   
   
  
   
   
   
  
  
  
  
 
 Photon as a wave packet of energy