chapter 18 cards
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- found out that changing electric fields could produce a magnetic field
- james maxwell
- b/c of changing electric and magnetic fields....
- they can create eachother
- electric charge moving back and forth
- electromagnetic wave
- changing an electric field to a magnetic field to an electric field
- oscillating charge
- transverse waves consist of changing electric and magnetic fields
- electromagnetic waves
- region of space that exerts electric forces on charged particles
- electric field
- region of space that produces magnetic fields
- magnetic field
- electromagnetic waves are produced when
- an electric charge vibrates or accelerates
- electromagnetic waves can travel through
- a vacuum, empty space or matter
- transfer of energy by electromagnetic waves traveling through matter or across space
- electromagnetic radiation
- measured the speed of light more accurately than before
- albert michelson
- the speed of light in a vacuum is
- 3.00 X 10>8 m/s
- in a vacuum
- all electromagnetic waves travel the same speed
- electromagnetic waves vary in
- wavelength and frequency
- electromagnetic radiation behaves sometimes
- like a wave or like a stream of particles
- the emission of electrons from a metal caused by light striking metal
- photoelectric effect
- proposed that light and all electromagnetic radiation consists of energy packets
- albert einstein
- packets of electromagnetic energy
- photons
- rate at which a wave's energy flows through a given unit of area
- intensity
- the intensisty of light decreases as photons
- travel farther from the source
- discovered infrared radiation
- william herschel
- full range of frequencies of electromagnetic radiation
- electromagnetic spectrum
- visible light
- is the only part we can see
- the electromagnetic spectrum includes
- radio waves, infrared rays, visible light, ultraviolet rays, x-rays, and gamma rays
- radio waves are used in
- radio and television technologies as well as in microwave ovens and radar
- longest wavelength
- radio
- lowest frequency
- radio
- amplitude of the wave is varied, frequency remains the same
- amplitude modulation
- am radio goes
- a lot longer but not as clear
- frequency of the wave varies amplitude remains the same
- frequency modulation
- fm stations
- clear but not as long
- acronym for RADAR
- Radio Detection And Ranging
- infrared rays are used as a
- source of heat and to discover areas of heat differences
- 1/100th of a millimeter
- nanometer
- color-coded pictures that show variations in temperature
- thermograms
- people use visible light to
- see and to communicate
- ultraviolet rays have applications in
- health, medecine and agriculture
- x-rays used in
- medecine,industry and transportation to make pictures of the inside of solid objects
- gamma rays are used in
- the medical field to kill cancer cells and make pictures of the brain
- since light travels so fast
- used as a yardstick to measure distance
- tried to measure speed of light with lanterns
- galileo
- will most likely move in a straight line
- light
- analyzed light in terms of mechanical particles
- sir issac newton
-
h -
e=hf - planck's constant ( 6.61 X 10 (-34)
- materials can be
- tranparent, opaque and translucent
- transmit light allows most of the light that strikes it to pass through
- transparent
- scatters light
- translucent
- either absorbs or reflects all the light that strikes it
- opaque
- when light strikes a new medium
- the light can be reflected, absorbed, or transmitted
- when light is transmitted
- it can be refracted, polarized and scattered
- copy of an object formed by reflected/refracted waves of light
- image
- when light reflects from a smooth surface
- see a sharp clear image
- when light reflects from a rough surface
- see a blurred reflected image or no image
- occurs when parallel light waves strike a surface and reflect all in the same direction
- regular reflection
- occurs when parallel light waves strike a rough uneven surface and reflect in different direction
- diffuse reflection
- false or distorted image
- mirage
- light with waves that vibrate in only one plane
- polarized light
- stops waves vibrating on a horizontal plane
- vertical polarizing filter
- means that light is redirected as it passes through a medium
- scattering
- visible light spectrum (prisms)
- issac newton
- as white light pases through a prism
- shorter wavelengths refract more than longer wavelengths and the colors separate
- process in which white light separates into colors
- dispersion
- the color of any object depends on what
- the object is made of and the color of light that strikes the object
- sunlight equals
- all colors of the spectrum
- three specific colors that can be combined in varying amounts to create possible colors
- primary colors
- the primary colors of light are
- red/green/blue
- combination of two primary colors
- secondary colors
- primary+proper secondary color=
- white light
- any two colors of light that combine to form white light
- complementary colors of light
- material that absorbs some colors of light adn reflects other colors
- pigment
- the primary colors of pigment are
- cyan, yellow and magneta
- any two colors of pigments that combine to make black pigment
- complementary colors of pigment
- objects that give off their own light
- luminous
- common light sources include
- incandescent, fluorescent, laser, neon,tungsten-halogen and sodium-vapor bulbs
- light produced when an object gets hot enough to glow
- incandescent
- when electrons flow through the filament of an incandescent bulb
- the filament gets hot adn emits light
- process where a material absorbs light at one wavelength and then emits light at a longer wavelength
- fluorescence
- solid material that can emit light by fluorescence
- phospor
- fluorescent lightbulbs emit light by causing
- a phospor to steadily emit photons
- small pieces of metal in a fluorescent bulb that heat up and emit electrons
- electrodes
- device that generates a beam of coherent light
- laser
- acrnoym for LASER
- Light Amplification by Stimulated Emission of Radiation
- laser light is emitted when
- excited atoms of a solid, liquid or gas emit protons
- light in which waves have the same wavelength and the crest/trough are lined up
- coherent light
- neon lights emit light when
- electrons move through a gas or a mixture of gases inside glass tubing
- helium
- pink
- argon
- greenish-blue
- krypton
- pale violet
- as electric current passes through a sodium-vapor bulb
- it ionizes the gas mixture
- the mixture warms up and heat causes the sodium to
- change from a solid to a gas
- inside a tungsten-halogen bulb, electrons flow through a tungsten filaments....
- the filament gets hot and emits light
- electromagnetic waves are __ waves consisting of changing electric and magnetic fields
- transverse
- objects that scatter some of the light that is transmitted through them are
- translucent
- combining equal amounts of the 3 primary pigments produce
- black
- electromagnetic waves can travel through a
- vacuum
- the electromagnetic waves with the shortest wavelengths are
- gamma rays
- a ___ or distorted image can be caused by the refraction of light as it moves into layers of hotter and hotter air
- mirage
- laser is an acronym
- Light Amplification by Stimulated Emission Radiation
- to form white light from the combination of only 2 colors that colors must be
- complementary
- light travels faster in
- air
- the ____ is the emission of electrons from metal caused by light striking the metal
- photoelectric effect
- the type of electromagnetic wave that has the longest wavelength/lowest frequency
- radio
- a ___is a thin coil wire stretched between two thicker wires in a lightbulb
- filament
- einstein showed that photoelectric effect could be explained if light consisted of photons each with energy where H is planks constant_____ and F is frequency
- 6.61 X 10>-34 J
- in the 1860s__realized that a changing electric field can produce a magnetic field
- james maxwell
- ____unsuccessfully tried to measure the speed of light using lanterns
- galileo
- since light travels so fast, it is used as a ___ to measure distance
- yardstick
- in 1926,____ measured the speed of light more accurately than before
- albert michelson
- ___ rate at which a wave's energy flows through a given unit of area
- intensity
- radar is an acronym for
- Radio Detection And Ranging
- a____ is 10>-9 meter
- nanometer
- a___ is a color-coded picture that shows variation in temperatures
- thermogram