1. Characteristics of Light
Light and Reflection
Characteristics of Light

2. Electromagnetic Waves
Electromagnetic waves – a transverse wave consisting of oscillating electric and magnetic fields at right angles to each other
Electromagnetic spectrum – a continuum of electromagnetic waves

3. Electromagnetic Waves

4. Electromagnetic Waves
Seven forms of electromagnetic radiation
Radio waves, microwaves, infrared waves, visible light, ultraviolet light, x-rays, gamma rays
Vary according to frequency and wavelength
Radio waves have the longest wavelength and shortest frequency
Gamma rays have the shortest wavelength and highest frequency
All forms of electromagnetic waves move at the speed of light ( *108m/s in a vacuum and *108m/s in air)
We will use 3.00*108m/s in both situations
c=fλ
Speed of light = frequency * wavelength

5. Electromagnetic Waves

6. Electromagnetic Waves
Waves can be approximated as rays (a straight line with an arrow head)
Called ray approximation
These lines represent wave fronts
When they strike a boundary, they produce a spherical secondary wave called a wavelet
Called Huygens’ principle in honor Christian Huygens who developed this approach to waves

7. Electromagnetic Waves

8. Electromagnetic Waves
Brightness of light decreases by the square of the distance from the source
The light spreads out, so less light is available per unit of area

9. Electromagnetic Waves