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148 Cards in this Set
- Front
- Back
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one of the first scientists to study light
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Sir Isaac Newton
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book in which Newton discussed colors and properties of light
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Optiks
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the idea that light is a stream of tiny particles emitted by the light source
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particle theory of light
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idea that light consists of waves
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wave theory of light
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scientist who proposed the particle theory of light
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Newton
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scientist who proposed the wave theory of light
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Robert Hooke and Christiaan Huygens
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showed that light consists of two transverse waves oscillating at right angles to each other
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James Clerk Maxwell
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kind of wave that makes up light
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electromagnetic wave
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medium through which electromagnetic waves travel
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none—they travel through space
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speed of light in a vacuum
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186,000 mi/s
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scientist who showed the existence of invisible electromagnetic waves
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Heinrich Hertz
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Hertz showed these kinds of waves act the same as light waves and so must be electromagnetic waves
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radio waves
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formula for speed of waves
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speed = wavelength x frequency
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units used for wavelengths of high-frequency waves
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nanometers
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units used to measure very short wavelengths
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angstrom
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what it is called when light above a certain frequency knocks electrons loose from atoms of certain metals
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photoelectric effect
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showed that light has characteristics of both waves and particles
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Max Planck and Albert Einstein
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theory which says light has both a wave and a particle nature
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quantum theory of light
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the property of light that indicates its wave/particle nature
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wave-article duality
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tiny packets of energy that make up light
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photons
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when photons act like particles
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when interacting with matter
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when photons act like waves
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when traveling through space
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final (?) definition of light
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electromagnetic waves traveling as photons
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electromagnetic waves that humans can see
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visible light
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range of visible light
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400-800 terahertz (THz)
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what causes color
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our brain's response to frequency
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six basic colors visible to the human eye
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red, orange, yellow, green, blue, violet
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the range of electromagnetic waves that humans perceive to have color
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visible spectrum
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color of the lowest visible frequencies
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red
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color of the highest visible frequencies
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violet
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a mixture of all visible colors
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white
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weak white light
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gray
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no visible frequencies, or the absence of color
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black
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short bar of glass with a triangular section
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prism
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what happens when white light passes through a prism
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it separates into its component colors by refraction
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the three colors that can add to form the illusion of any other color
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additive primary colors (red, green, blue)
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additive mix of blue and red
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magenta
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additive mix of green and red
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yellow
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additive mix of green and blue
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cyan
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the subtractive primary colors which using pigments can form the illusion of any other color
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magenta, cyan, yellow
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additive primary colors refer to ______
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light
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subtractive primary colors refer to ______
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pigment (ink, paint, etc.)
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the angle of incidence equals the angle of reflection
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the law of reflection
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two types of images formed by light and a mirror
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virtual image, real image
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apparent placement of a virtual image
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behind the mirror
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apparent placement of a real image
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in front of the mirror
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type of image usually produced by a flat mirror
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virtual image
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mirror that forms part of a spherical surface
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spherical mirror
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shape of a mirror if it is on the inside of a spherical surface
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concave
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shape of a mirror if it is on the outside of a spherical surface
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convex
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what makes the reflection of light from a mirror form an image while the reflection of light off of, for instance, a piece of paper does not form an image
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the surface of the mirror is very smooth
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causes a straw in a glass of water to appear bent at the water's surface
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refraction
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causes refraction of light and other waves
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change of medium (because waves travel at different speeds in different media)
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in which direction to refracted light waves bend
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toward the medium that slows them down
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useful application of refraction
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eyeglasses and contacts, cameras, binoculars
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piece of glass or other substance specially designed to refract light
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lens
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direction a convex lens curves
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outward
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direction a concave lens curves
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inward
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purpose of a convex lens in glasses
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to magnify objects to correct farsightedness (hyperopia)
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purpose of a concave lens in glasses
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to cause objects to appear more distant, to correct nearsightedness (myopia)
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opening in a camera lens
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aperture
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used to control the aperture in a camera
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diaphragm
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occurs when light rays from a distant object are refracted by heated air so that the object appears to be nearby
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mirage
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twinkling of stars caused by refraction
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scintillation
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semicircular arc of colored bands of light in the sky
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rainbow
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conditions that allow for sighting of a rainbow
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rain is falling in front of viewer (or there is a heavy mist) and sun's rays are shining from behind viewer
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results from light rays that reflect twice instead of once inside water droplets
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secondary rainbow
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the mutual reinforcement or cancellation (addition or subtraction) of meeting waves
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interference
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what is true when waves are in phase
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they have the same frequency, travel in the same direction, and have their crests and troughs aligned
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when light waves are in phase, how they appear
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brighter
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when light waves are out of phase, how they appear
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darker
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process in which colors are produced by interference when light is reflected
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iridescence
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the spreading of a wave as it passes by an obstacle or through a narrow gap
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diffraction
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place diffraction of light waves is seen every day
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shadows
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the lighter edge surrounding a shadow
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penumbra
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the darkest part of a shadow
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umbra
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light fringes formed by diffraction when light passes through a narrow opening
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antinodes
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dark fringes formed by diffraction when light passes through a narrow opening
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nodes
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when light comes from a single source and in a single wave train
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coherent light
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tool that produces spectra in the laboratory
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diffraction grating
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the speeding up or slowing down of light waves when the source is in motion relative to the observer
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Doppler effect
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why the Doppler effect of light is not ordinarily observable
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change in frequency is too small
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a beam of light containing waves that are all aligned in the same direction
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polarized
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ways to polarize light
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polarization by reflection, polarization by selective absorption
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shows all electromagnetic waves in order of frequency and wavelength
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electromagnetic spectrum
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categories of waves from low to high frequency/long to short wavelength
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electric power waves, radio waves, microwaves, infrared waves, visible light, ultraviolet light, x-rays, gamma rays
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low-frequency electromagnetic waves used for communications
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radio waves
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produces the lowest-frequency radio waves
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long wave radio transmitters
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uses of radio waves from lowest to highest frequencies
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ship and airplane communication and navigation; AM radio; shortwave radio; television and FM radio, cell phones
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uses microwaves to cook food
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microwave oven
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other uses of microwaves
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GPS, radar, communications satellites
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system that transmits information about location and time from several satellites
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Global Positioning System (GPS)
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number of satellites information is needed from to pinpoint your location on earth
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4
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what radar stands for
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radio detection and ranging
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what radar is used for
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to measure the distance and direction of faraway objects
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determines an object's speed by measuring the Doppler-effect frequency shift of a radar beam reflected off it
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Doppler radar
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called heat rays because they transmit radiant heat
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infrared rays, perceived as warmth
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three categories of ultraviolet radiation
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UVA, UVB, UVC
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the lowest frequency and least dangerous kind of UV rays
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UVA ("black lights")
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UV rays which can severely damage or even kill cells in the upper layers of the skin
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UVB
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painful swelling of damaged skin tissue caused by UVB rays
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sunburn
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thing in atmosphere that blocks most UVB
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ozone layer
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completely blocked by the ozone layer
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UVC
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benefit of UV on our skin
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produces vitamin D by breaking down sterols
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discovered X-rays
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Wilhelm Roentgen
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what causes the usefulness of X-rays
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they can penetrate many solid materials, allowing doctors to "see" inside the body
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rays that can penetrate nearly anything
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gamma rays
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medical use for gamma rays
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radiotherapy
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machines that use gamma rays to sterilize medical supplies
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irradiators
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what the energy of a photon depends on
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its frequency
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energy levels in an atom
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electron shells
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objects that glow when illuminated by ultraviolet light
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fluorescent objects
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glow-in-the-dark objects
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phosphorescent
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what happens when a photon of light strikes an electron
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it goes to a higher energy level temporarily; when it returns to the original, it emits a photon of light
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what happens when a photon of light strikes an electron already at a high level
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it emits two photons of light and reverts to a much lower energy level
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name for the emission of extra photons by highly energized electrons
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stimulated emission
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generates and amplifies high-energy beams of light
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laser
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what laser stands for
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light amplification by stimulated emission of radiation
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constructed the first laser
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Theodore Maiman
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kind of laser that was the first laser
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ruby laser
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how laser is different from flashlight light
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it consists of a single frequency
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name for light beams that have only one frequency
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monochromatic
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property of laser beams that means they are all in phase
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coherent
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three properties of laser light
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monochromatic, coherent, extremely intense
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how the first laser was pumped
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optically
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well-known electrically pumped laser
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helium-neon laser
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laser of green light
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argon laser
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laser of infrared light used in industry
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carbon dioxide laser
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laser which produces multiple colors
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dye laser
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tiny laser
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gallium arsenide laser
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fields which use lasers
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communications, medicine, military, industry
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machine most people use daily that uses lasers
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CD player
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technique for transmitting light through optical fibers
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fiber optics
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laser developed for the military but now used in other places as well
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free-electron laser
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3-D image produced by a laser
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hologram
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principle holograms work on
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wave interference
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speed of light in a vacuum
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186,000 mi/sec.
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what is true about the speed of light in a vacuum
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it is constant—a universal constant
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developed a theory based on the constancy of the speed of light
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Albert Einstein
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name of Einstein's theory
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special theory of relativity
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4 ideas from the theory of relativity that are based on the speed of light remaining constant
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time dilation, length contraction, mass increase, universal speed limit
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what time dilation means
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apparent slowing of time when objects are moving at high speeds
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what length contraction means
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objects appear shorter in the direction of motion (at high speeds)
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name for length contraction
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Lorentz contraction
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what mass increase means
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the mass of an object at high speed seems to increase to an observer
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what universal speed limit means
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nothing in the physical universe can travel faster than light in a vacuum
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Einstein's theory that gravity was a result of the geometry of space
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general theory of relativity
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according to the theory of relativity, gravity affects what
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time and length
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