Chapter 13Chapter 13SoundSound

Section 1Section 1

►Electromagnetic waves made by vibrating electric charges and can

travel through space.

►Electric and magnetic fields related forces operate even in empty space Moving electric charge creates magnetic field Changing magnetic fields create changing

electric fields and vice versa.

►Electromagnetic waves produced when an electric charge is vibrating

►Vibrating electric charges are surrounded by vibrating electric and magnetic fields

►Properties of Electromagnetic fields carry radiant energy as frequency increases, wavelength

decreases►Frequency

number of vibrations per second measured in hertz

►Wavelength is the distance from one crest to another measured in meters

►Wave speed the vacuum of space, 300,000 km/s electromagnetic waves slow as they travel

through matter

Waves and particles►Difference is still not clear

►Light can behave as a particle or waveKnow as duality

►PhotonParticle of light whose energy depends on frequency

►All particles can behave like a wave

Section 2Section 2

►Electromagnetic spectrum Entire range of electromagnetic wave frequencies

►Radio waves low-frequency electromagnetic waves with

wavelengths from less than a cm to about 1000 m

►Microwaves radio wave lengths of about 1 to 10 cm

►Radar radio waves bounced off an object to determine

its speed and location

►Magnetic Resonance Imaging (MRI) radio waves produce an image of inside the body

► Infrared waves slightly higher frequency than radio waves people feel it as thermal energy or warmth

►Visible light wavelengths between ~390 to 770 billionth of a

meter can be seen with the eye

►Ultraviolet waves Have frequencies slightly higher than visible light;

can damage skin

►Ultraviolet light can kill bacteria can be absorbed by some fluorescent materials and

released as visible light

►Ozone layer absorbs most of the Sun’s harmful ultraviolet waves.

►X rays and gamma raysultra-high-frequency electromagnetic waves that can travel through matter, break molecular bonds & damage cells

►X raysused to provide images of bones and to examine suitcases at airports without opening them.

►Radiation therapyused to kill diseased cells

Section 3Section 3

►Radio transmission radio converts electromagnetic waves into

sound waves

►Carrier wave specific frequency which radio station is

assigned

►AM radio broadcast by varying amplitude of carrier wave frequencies range from 540 to 1,600 thousand

vibrations per second

►FM radio transmit by varying frequency of carrier wave frequencies range from 88 million to 108

million vibrations per second

►Television sounds and images changed into

electronic signals broadcast by carrier waves

► Audio sent by FM radio waves

►Video sent by AM signals

►Cathode-ray tube A sealed vacuum chamber with a

coated screen that receives electron beams to provide images

►Telephones microphone converts sound waves into

electrical signal

►Cell phone electrical signal creates a radio wave that

is transmitted to and from a microwave tower

►Cordless phone transceiver sends one radio signal &

receives another at different frequency from base unit

►Pagers radio receiver on which a message is left

►Communication satellites high frequency microwave signal is transmitted

to a satellite satellite amplifies it and returns it to Earth at a

different frequency

►Satellite telephone systems mobile phones transmit radio signals to a

satellite satellite relays them back to a ground station

that passes the call into the telephone network

►Television satellites uses microwaves rather than longer-wavelength

radio wave ground receiver dish focuses the microwave

beam onto an antenna

►Global positioning systemsystem of satellites, ground stations, and receivers that provide information about the receiver’s location on or above the Earth’s surface

►G.P.S.G.P.S.