Summary

• The human eye
• The magnifying glass
• The telescope

• Class quiz
  
  
  
• Diffraction & resolution
  • circular apertures
  • Rayleigh criterion
    Example #1
    
    Example #2
    
    
  
  
  
• Galilean relativity
  • frames of reference applet
  • adding velocities
  • videos
  • Galilean principle
    
    Example #3
    
  
  

gc6 25.tb.21
A refracting telescope has a magnification m. If the objective focal length is doubled and the eyepiece focal length is halved, what is the new magnification?
A. 4m          B. 2m          C. m          D. m/4
Answer







gc6 25.tb22
With what color light would you expect to be able to see the greatest detail when using a microscope?
A. red, because of its long wavelength
B. green, because the eye is most sensitive to green
C. blue, because of its shorter wavelength
D. Color does not matter.
Answer







gc6 25.49mod
What minimimum diameter telescope on Earth is required to resolve objects on the Moon's surface that are 1.0 km apart? λ = 550 nm and L = 3.84×10⁸ m.
A. 2.06 m                B. 0.918 m
C. 0.774 m              D. 0.258 m
Answer







kw5 tb9.7
While you are standing on the ground, you observe your friends pass by in a van traveling at a constant velocity. They drop a ball and you all make measurements of the ball's motion. Which of the following quantities has the same value in both reference systems?
A. velocities            B. kinetic energies
C. forces                 D. momenta
Answer







 



A. 4m













 



C. blue, because of its shorter wavelength
The resolving ability of a microscope is limited by the diffraction of light through its optical elements. Shorter wavelengths will diffract less and provide better resolution. Electron microscopes have the best resolution because they use electrons that have much shorter "wavelengths" than does visible light.













 



D. 0.258 m













 



C. forces
The two observers disagree on the distances traveled and the speeds, but they agree upon the laws of physics, which in this case is F = ma. That is, the force, mass, and acceleration of the ball is the same for each observer.