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Physics chapter 28

chapter 28

QuestionAnswer
What is color caused by? caused by the frequencies of light that are given off or reflected by an object
where is color blindness of defective cones result? in the retina of the eye.
who was the first person to really explore color in detail? Isaac Newton
what did he do? passed a beam of sunlight through a glass prism
what did issac see? white light separate into a series of different colors
what is a spectrum? a ranfe
what is the color spectrum? a range of color
What are the colors in the color spectrum? red, orange, yellow, green, blue, violet
What is white light a combination of? all colors of light
What is an example of white light? sunlight
white light is not truly a combination of all colors. who figured this out? newton
is black a color? no it is the absence of any of the colors of light
how is the color of an object determined? by the frequencies of light that are reflected back from the object
Can all frequencies be reflected? no some frequencies of light may be absorbed
what do all materials have? a natural frequency
when does resonance occur? if the natural frequency matches any of the frequencies of light. and the frequency will remain
for what materials will re-emitted light continue through? transparent
for opaque material what happens? re-emitted light is reflected back
What do most materials do? will absorb some frequencies and reflect some
why is the type of light source important? because an object can reflect only light of frequencies present in the light source
what are the different kind of light sources? candlelight, incandescent, fluorescent
For transparent what does the object depend on? the light that is transmitted
what is a pigment the material which absorbs particular colors of light
What is sunlight? a combination of all frequencies of visible light.
what else is sunlight? a combination of all the colors of the spectrum
red+blue= magenta
blue+green= cyan
green+red= yellow
green+red+blue= white
what are additive primary colors? three colors that when added together make white
What do TV screens use? additive colors
what happens when the TV is on? the spots are lit red, blue, or green
What are complementary colors? two colors that when added together form white
how can only two colors do this? one of the two colors must be a combination of two additive primary colors
What are examples of the two colors? 1. yellow+blue= white 2. magenta+green=white 3. cyan+red=white
where are complimentary colors on the color wheel opposite of each other
when using complimentary colors is it possible to determine what light color would be seen if particular colors were removed from white light? YES
when mixing paint is it different than mixing light? yes
when mixing red green and blue light what does the color become? white
when mixing red and green and blue paint what do the colors become brown
what does paint and dyes contain? pigments
how do paints and dyes get their color? by color mixing by subtraction
how does light get its color? by color mixing by addition
what are the subtractive primary colors? magenta, cyan, and yellow
what are subtractive primary colors used for? printing
what is scattering? is a process in which sound or light is absorbed and reemitted in all directions
how is light scattered? by molecules and larger specks of matter that are far apart from one another in the atmosphere
what happens when the particle size is smaller? the higher the frequency is scattered.
what is the order of the colors that are scattered the most? violet, blue, green, yellow, orange, and red
when there are a lot of particles larger than oxygen and nitrogen molecules what happens to the frequency? the lower the frequencies of light are scattered more
what happens when there are no molecules? the sky is black
what makes up clouds? water droplets in a variety of sizes
The different-size droplets of water molecules result in a variety of frequencies for scattered light: 1. low frequencies from larger droplets 2. high frequencies form tinier droplets
what is the overall result? a white cloud
what do larger particles scatter? lower frequencies
what is the atmosphere nearer the earth made up of? larger particles
what are the lower frequencies? red
At sunrise and sunset how does light travel? longer path through the atmosphere
Why is water greenish blue? because water molecules absorb red
what is the true color of ocean water? cyan
why is the froth in the wave white? because its droplets of many sizes scatter many color frequencies
why does the water look sometimes deep blue? it is a reflection of the color of the sky
what is water transparent to? all frequencies of light
what does water absorb? infrared frequencies
how is water warmed? by sunlight
what do water molecules resonate to? visible red frequencies
what does every element have? has its own characteristic color when it emits light
what is the color a blend of? various frequencies of light
when is light of each frequency emitted? when the electrons change energy states
do electrons have well-defined energy levels? yes the lower energy near the atomic nucleus and higher energy father from the nucleus
what happens when an atom absorbs external energy? one or more of its electrons is boosted to a higher energylevel
what state is an energized atom in? excited state
what is an excited state? a state with greater energy than the atom's lowest energy state
how long does the excited state last for? it is only momentary, for the electron is quickly drawn back to its original or a lower level of energy
what is a photon? a pulse of light
what do the different electron orbits in an atom look like? steps in energy levels
what happens when an electron is raised to a higher level? the atom is excited
what happens when the electron returns to its original level? it releases energy in the form of light
what is a spectroscope? an instrument that analyzes light from glowing elements
what did Newton's spectroscope use? two lenses a thin slit, and a prism to produce a clear spectrum from white light
what does an incandescent bulb have? a continuous spectrum
what three elements have a different line spectrum? hydrogen, sodium, and mercury
who can use the line spectra and what for? chemists can use the line spectra for identifying an element just as a fingerprint can be used to identify a person
how can the atomic composition of the sun and distant galaxies be determined? by examining the line spectra.
Created by: 16_dnuckolls