Chapter 38: Diffraction Patterns

• Diffraction: The general idea, and why it is not observed with light in everyday day.
   
• Diffraction pattern from a narrow slit: The condition for destructive interference from a narrow slit of width a giving dark fringes on a distant screen, is

a sin θ = mλ ,   with   m = ±1, ±2, ...

• Diffraction grating: The general idea.

The rest of the chapter was not covered.