Chapter 14 - LightElectromagnetic Wave- a wave that consists of vibrating electric and magnetic fields that radiate outward from the source at the speed of light.

Speed of Light (c) c=3.00 x 108 m/s

Electromagnetic Spectrum- from least frequency to greatest- Radio Waves, Microwaves, Infrared, Visible Light, Ultraviolet, X-rays, Gamma Rays

• Radio Waves – AM & FM radio, Television broadcasts > 30 cm, f < 109 hz

• Microwaves- radar, aircraft navigation, microwave ovens, research

30 cm>>1 mm, E 9 hz<f< 3 E11 hz

Infrared- physical therapy, infrared photography, molecular spectra

1 mm>>700 nm, 3 E11 hz<f<4.3 E14 hz

Visible Light- 700 nm(red)>>400 nm(violet)

4.3 E14 hz< f < 7.5 E14 hz

• Ultraviolet- sterilize medical instruments, identify fluorescent minerals, sunburn

400 nm>>60 nm,

7.5 E14 hz< f < 5 E15 hz

X-rays- medical exam of bones, teeth and organs, treatment for types of cancer

60 nm>> 1E-4 nm

5 E15 hz < f < 3 E21 hz

Gamma Rays- treatment for cancer, food irradiation, exam for structural flaws

Wave speed equation for light c = f

Two basic theories of light- Wave Theory, Particle Theory. Light acts like both at different times.

Wave Theory- has a wavelength, frequency, starts with a vibration, can have interference (constructive and destructive), polarization

Particle Theory- reflection, refraction, ray diagrams

• Law of Reflection- the angle at which light strikes a surface with respect to the Normal (perpendicular line to the surface), is equal to the angle at which light leaves the surface.

• Angle of incidence = Angle of reflection

• Diffuse reflection- the reflection off of a rough surface – no glare

• Specular reflection- smooth surfaces, such as glass and water.

Flat Mirrors

• Virtual image is formed, that appears to be behind the mirror at the same distance as the object in front of the mirror.

• Images will be the same size as the object.

• The image formed is reverse of the object.