Chapter 17

Front 1

Electromagnetic waves

Back 1

-transverse waves
-have some electrical and magnetic properties
-do not require a medium to travel

Front 2

Electric and magnetic fields

Back 2

-electromagnetic waves travel as vibrations in electric and magnetic fields
-a moving electric charge is surrounded by a magnetic field.
-two fields constantly cause each other to change

Front 3

Electromagnetic radiation

Back 3

-is the energy transferred be electromagnetic waves

Front 4

Speed of electromagnetic waves

Back 4

-all 300,000,000 meters per second- speed of light
-this also means that since speed is the same, if the wavelength is shorter, the frequency is higher. if the wavelength is longer, frequency is lower.

Front 5

properties of light

Back 5

both:
-particles
-waves

Front 6

polarized light

Back 6

light that passes through a polarizing filter

Front 7

photoelectric effect

Back 7

movement of electrons (particles) out of a substance
-caused by photons in light

Front 8

photon

Back 8

packets,or particles,of energy

Front 9

Characteristics of electromagnetic waves

Back 9

-all travel at the same speed
-but have different wavelengths and frequencies.
speed=wavelength x frequency

Front 10

electromagnetic spectrum

Back 10

the name of the range of the electromagnetic waves when they are placed in order of increasing frequency.

Front 11

radio waves

Back 11

longest wavelength and lowest frequency

Front 12

microwaves

Back 12

shortest wavelength and highest frequency

Front 13

radar

Back 13

Radio Detection And Ranging.
-waves are sent out and reflected by objects they strike.
-receiver detects them and measures the time it takes for them to come back

Front 14

magnetic resonance imaging
(MRI)

Back 14

-radio waves and strong magnetic fields cause atoms in the body to line up in the same direction
-they return to their original directions at different rates.
-it uses the responses to create images of organs

Front 15

infrared rays

Back 15

shorter wavelengths and higher frequencys
-felt as heat
-infra=below
-infra are below red

Front 16

thermogram

Back 16

a picture that shows different temperatures in different colors

Front 17

visible light

Back 17

shorter wavelengths and higher frequencies than infrared waves

Front 18

ultraviolet rays

Back 18

-wavelengths shorter than that of visible light
-ultra=beyond
-ultraviolet means beyond violet
-small doses are beneficial, large doses can cause cancer.
-used to kill microorganisms

Front 19

x-rays

Back 19

-very short wavelengths
-because of the high frequency, x-rays carry more energy than ultraviolet rays and can penetrate most matter
-to much exposure can cause cancer

Front 20

gamma rays

Back 20

-shortest wavelength and highest frequencies of the electromagnetic spectrum.
-can be used to treat cancer
-used to irradiate food and kill microorganisms

Front 21

illuminated

Back 21

object reflects light so it can be seen

Front 22

luminous

Back 22

object gives off its own light

Front 23

spectroscope

Back 23

instrument used to view the different colors of light produced by each type of light bulb

Front 24

incandescent lights

Back 24

-glow when filament inside gets hot
-not very efficient
-lot of energy given off as heat
-filament is tungsten surrounded by inert gases

Front 25

fluorescent lights

Back 25

-when an electric current passes through
-the current causes gas in the bulb to give off ultraviolet wave
-these waves react with a powder in the bulb to give off visible light
-more efficient then incandescent lights

Front 26

neon lights

Back 26

-tubes filled with neon gas react to an electric current
-the gas particles can not hold the energy for very long
-so it is released as light
-creates red light
-other gases are used to create other colors of "neon" lights

Front 27

sodium vapor lights

Back 27

-small amount of solid sodium, neon, and argon gasses are used in these lights
-neon and argon are heated causing the sodium to vaporize and give off energy in the form of light
-give off very bright, economical, and yellow light

Front 28

Bioluminescence

Back 28

organisms that create their own light

Front 29

Am radio

Back 29

-frequency consistent
-amplitude varies
-amplitude modulation 535-1,605 kHz

Front 30

FM radio

Back 30

-amplitude consistent
-frequency varies
-frequency modulation 89-108 MHz

Front 31

television

Back 31

-UHF (ultra high frequency- channels 14-69, 470-804 MHz)
-VHF (very high frequency- channels 2-13, 54-216 MHz)

Front 32

cellular telephones

Back 32

-transmit and receive very high frequency radio waves
-use towers to transmit and receive signals

Front 33

cordless telephones

Back 33

- radio waves communicated between the handset and the base
-limited range not like cellular phones

Front 34

pagers

Back 34

allow people to send text or numeric messages

Front 35

communications satellites

Back 35

-used to transmit signals across a greater area.
-used in communications, televisions, telephones, etc.

Front 36

satellite telephone systems

Back 36

-use satellite signals to transmit the communication
-works anywhere in the world but much more expensive

Front 37

television satellites

Back 37

used to transfer signals to local stations where the signal is changed into radio waves

Front 38

global positioning system

Back 38

use satellites to identify location. can use one or more satellites together to find or determine location