Summary

• Huygens' principle

• Young's interference applet
  another applet
  
  Example #1
  
  Example #2
  
  
  
  
• Dispersion
  • prism
  • rainbows applet
    
    Example #3
    
  • halos and sun dogs
  • more on atmospheric optics
  
  
  
  
  
• Diffraction
  • principle
  • single-slit applet
    another applet
    
    Example #4
    
    Example #5
    
  • gratings (Figures 24-25 and
    24-27 applets)
    
    Example #6
    
  
  

gc6 24.q6
Blue light is shined through two slits to produce an interference pattern on a screen. What will happen to the pattern if red light is used instead?
  A. The pattern will not change.
  B. The pattern will condense.
  C. The pattern will expand.
  D. The pattern will be too dim to see.
Answer







gc6 24.4
Light of wavelength 656 nm falls on two narrow slits 0.060 mm apart. How far apart are the fringes on a screen 3.6 m away?
A. 6.56 cm             B. 3.94 cm
C. 1.14 cm             D. 0.77 cm
Answer







kw4
Blue light has a higher index of refraction in glass than does red light. A glass lens will thus have a blue focal length that is _____ its red focal length.
A. shorter than             B. longer than
C. the same as
D. depends on whether lens is converging or diverging
Answer







gc6 24.q17
Blue light is shined through a single slit to produce a diffraction pattern on a screen. What will happen to the pattern if red light is used instead?
  A. The pattern will not change.
  B. The pattern will condense.
  C. The pattern will expand.
  D. The pattern will be too dim to see.
Answer







gc6 24.24
When light of λ = 415 nm falls on a single slit, it creates a central diffraction peak that is 9.20 cm wide on a screen 2.55 m away. How wide is the slit?
A. 301 µm              B. 9.02 µm
C. 18.0 µm             D. 23.0 µm
Answer







gc6 24.33
Light falling normally on a 9700 line/cm grating produces a first-order bright line at 36.4°. What is the wavelength of this line?
A. 612 nm               B. 970 nm
C. 1031 nm             D. 364 nm
Answer







 



C. The pattern will expand.
Red light has a longer wavelength than blue, and the separation between adjacent maxima in the interference pattern is linearly dependent upon the wavelength.












 



B. 3.94 cm













 



A. shorter than
Snell's law predicts more ray bending by a large index of refraction than by a small index of refraction. Thus parallel blue rays that enter the lens will be bent more sharply than red rays, and the blue focal length will be shorter, both for converging and diverging lenses.












 



C. The pattern will expand.
Red light has a longer wavelength than blue, and the separation between adjacent maxima in the diffraction pattern is linearly dependent upon the wavelength.












 



D. 23.0 µm













 



A. 612 nm















More photos of halos

This picture was taken at the south pole, and includes a great number of interesting optical effects created by pencil-shaped and plate-shaped ice crystals.


These are the ice crystals responsible for some of the effects you see in the above photo


This picture was taken in Alaska, and shows some color in the sun dogs and other effects that result from slight dispersion in ice.