1. The Nature of Electromagnetic Waves
Unit 4 Waves
The Nature of Electromagnetic Waves

2. Reminder… waves transfer energy w/o transferring matter
mechanical waves, like water waves & sound waves, transfer energy by making particles of matter move (but not electromagnetic waves)

3. Electromagnetic Waves
electromagnetic waves - produced by charged particles (electrons or protons) in motion
do not use matter to travel

4. Electromagnetic Waves: Made of 2 Force Fields
Magnetic Field
Electric Field
magnetic field - a force field around a magnet that causes other magnets to line up w/ the direction of the field
electric field - a force field around a charged particle (electron or proton) that attracts other charged particles

5. Making Electromagnetic Waves
electromagnetic waves are made when charged particles (electrons/protons) move
a charged particle makes an electric field BUT… a moving charged particle makes an electric field AND a magnetic field
ex. when an electric current flows through a wire, electrons are moving in the wire, which causes an electric field in the wire & a magnetic field around the wire

6. Properties of Electromagnetic Waves
wavelength - one complete vibration of a charged particle
frequency - the number of times the charged particle makes a complete vibration in 1 second
higher frequency of EM. waves = more energy
radiant energy - the energy carried by an electromagnetic wave
all EM. waves travel at the same speed (300 million m/s)