Optics Questions

• Can air make shadows?
• Can you make a shock wave of light by breaking the light barrier just like supersonic airplanes break the sound barrier?
• How do projectors project the color black?
• Why can't flat lenses focus light?
• Why do mirrors flip left to right and not up to down?
• Why does a rainbow contain a pure spread of spectral colors?
• Why does a rainbow exist only in a narrow band?