LIGHT (Ch. 16) “Many hands make light work”

What makes light work? Maxwell's Equations  J.C. Maxwell  4 Equations  Explain all of E- Mag  Survived since before Einstein

What is light? Light is...  … electromagnetic waves Diffraction Interference – Double-Slit Experiment – Single-Slit Experiment  … particles Isaac Newton called them “corpuscles” Photoelectric Effect

What is light? Light is...  … Umm … It cannot be both... Can it?  Particles do not diffract or interfere  Waves cannot cause the photoelectric effect Whichever it is, we can use rays to describe it.

That is fast!! The speed of light  Thought to be infinite  Galileo did not agree He tried to measure the speed but was unable  17 th century Dutch astronomer Ole Roemer Calculated it to be 2.2×10 8 m/s  Albert Michelson Measured speed of light to be 3×10 8 m/s  This is a constant: c = 3×10 8 m/s

Roy G. Biv Light can be separated into different types depending on (depending how you look at it) wavelength, frequency, or energy – Radio – Microwave – Infrared – Visible – Ultraviolet – X-Ray – Gamma Ray

Roy G. Biv All we can see is called visible light, and it is a tiny portion of all light. It is further separated into colors, the colors of the rainbow – Red – Orange – Yellow – Green – Blue – Indigo – Violet

Roy G. Biv Primary Colors of Light – Red – Green – Blue Secondary Colors – Cyan – Magenta – Yellow All colors together – White

Polar Bears Each light wave is only oriented a certain way. Some materials block light that is not oriented a certain way. These are called polarizers. Polarizers can be quite useful, and interesting and fun! – Polarized Sunglasses – Newer 3-D glasses

Doppler Effect Just like sound waves, light waves can also be shifted in frequency/wavelength by the Doppler Effect. The equation is a little bit different, although similar

Equations

Assignment Chapter 16 – (page 447) – 52, 60, 63 (pp )