A. EM waves are transverse waves that have electrical properties and
magnetic properties.
B. EM Radiation is energy transferred in EM waves.
1. All EM Radiation travels at the speed of light
2. Speed = 300,000,000 m/s (186,000,000 miles/s)
3. Can travel through solid, liquid, gas, and a vacuum.
4. Light takes 8 mins to travel from the sun to the earth.
5. Medium can change speed of wave
C. Duality of Light: Is it a wave or a particle?
1. Acts like a wave
Polarized glasses
2. Acts like a particle
Photons
D. EM Spectrum: Shows the different EM waves in order of increasing frequency and decreasing wavelength.
Long Wavelength
Low Frequency
Low Energy
Short Wavelength
High Frequency
High Energy
Wavelength = wl
Frequency = freq
Rays = Waves
A. Radio waves: EM waves with the longest wl and the lowest freq.
1. Size: Longer than a football field to the width of a baseball
2. Uses: Radio and TV waves picked up by antenna and converted into
sound and picture. AM and FM.
3. Radio Telescope: Used in Astronomy.
B. Microwaves: Short radio waves with higher frequencies.
1. Size: Baseball to a period.
2. Uses: Microwave ovens, Cell Phones, and Radar.
3. Satellite Communications and MRI
C. Infrared Rays: Have shorter wl and higher freq than radio.
1. Size: Human cell to a bacteria cell
2. Uses: Cooking, Heat Lamps, Warmth from Sun
3. Green House Effect
D. Visible Light: EM waves that you can see
1. Size: Shorter wl and higher freq than infrared.
2. Uses: Sight, Telescopes, Lighting
3. ROYGBIV = The Visible Spectrum
E. Ultraviolet Rays: EM waves with wls just shorten than visible.
1. Size: Virus
2. Uses: Sterilizing, Vitamin D for healthy Bones, Insect Vision
3. Sun Burns and Skin Cancer
F. X-rays: EM waves with very short wls
1. Size: Protein Molecule to H20
2. Uses: Medical, Satellites, Detect Black Holes
3. Can cause Cancer and penetrate most matter
G. Gamma Rays: shortest EM waves with the greatest energy.
1. Size: Atom to smaller
2. Uses: Kill cancer, Hubble Telescope,
3. Cause Cancer and most penetrating EM waves.