Unit 4 Waves The Nature of Electromagnetic Waves

Unit 4 Waves The Nature of Electromagnetic Waves

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)

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

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

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

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)