Light and Optics PHYS 1090 Unit 8

Speed of Light c =  10 8 m/s (in vacuum)

Electromagnetic Wave Energy Non-classical result: E = hf E = energy f = frequency h = Planck constant =  J s

Electromagnetic Spectrum

Emission Lines Hydrogen Helium Neon Sodium Source: J. Strasbourg,I. Kiel after J. Tabbot. Data from NIST.J. Strasbourg,I. Kiel NIST

Hydrogen Emission “Thousand Ruby Galaxy” M83 Source: European Southern Observatory

Spectrum of the Sun Source: McMath-Pierce Solar Observatories

Reflection and Transmission (and absorption)

How Human Color Vision Works Source: Griffith, Physics of Everyday Phenomena

Primary Colors redgreenblue

Bird and Reptile Color Vision Source: Scientific American, July 2006

Different material (like glass) Incident medium (like air) Light Interacting with a Material INCIDENT RAY REFLECTED RAY TRANSMITTED RAY

Refraction refracted ray AIR GLASS Normal (air-glass) Incident ray Normal (glass-air) transmitted ray

Lens Properties A lens can either cause the rays to converge or diverge

Using Rays Ray tracing diagrams predict the location, orientation, and type of an image

Colors Split by Dispersion Source: Griffith, Physics of Everyday Phenomena, 4 ed.

Speed in Glass Depends on Index of refraction n = c/v c = vacuum speed v = speed in medium

Source: Griffith Prism Separates White Light

Primary Rainbow: 1 Reflection Source: Griffith, Physics of Everyday Phenomena 40° 42°

Secondary Rainbow: 2 Reflections Source: Griffith 54.5° 52°

Dispersion Creates Rainbows Source: Griffith

Diffraction and Interference Wave behavior You observed it with water waves It happens with light waves!

Temp Influences EM Radiation Higher T  greater power – P/A =  T 4 –  = 5.67  10 –8 J m –2 K –4 Higher T  higher peak frequency – max = b/T – b =  10 6 nm K Source: M. A. Seeds, Exploring the Universe