Light Waves

A. ELECTROMAGNETIC WAVES

1. Do not require a medium to travel through

2. They transfer energy without transferring particles

3. Travel by transferring energy between vibrating electric and magnetic fields

Ex: an electric charge that moves back and forth

A. ELECTROMAGNETIC WAVES

B. PROPERTIES OF ELECTROMAGNETIC WAVES

1. Radiant energy: the energy carried by an electromagnetic wave.

2. Wave speed a. travel at the speed of light (in a vacuum)

~ 2.99 x 108 m/sec b. depends on the medium it travels in

~ travels the slowest in solids

C. OTHER USES1. RADAR – Radio Detecting and Ranging

~ measures the time required for the radiowave to bounce off of object

2. MRI – Magnetic Resonance Imaging~ different tissues absorb different amounts of radio

waves and emits radiant energy

3. Infrared Waves ~ remote controls, CD-ROMs, snakes, firefighters, police

4. UV – Ultraviolet Light~ useful to kill bacteria, our ozone, fingerprinting

5. “X-Rays” – x-rays and gamma rays~ absorbed by bones and not by soft tissue

VISIBLE LIGHT INFRARED

WHAT A SNAKE “SEES”

D. Behavior of Light waves

1. Interferencea. Light waves

1. Constructive – brighter light 2. Destructive – dimmer light

2. Light waves travel faster in gases and empty space than in liquids and solids