Properties of Light .


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Models of Light. Socrates and Plato trusted \"streamers\" or radio wires were discharged from the eyes. . Euclid and Descartes had comparative speculations. . Greeks thought anything that could be seen radiated light waves. . Models of Light. Newton presented the molecule hypothesis. He said that light goes in straight lines not at all like waves. .
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Section 27 Properties of Light

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Models of Light Newton presented the molecule hypothesis. He said that light goes in straight lines dissimilar to waves.

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Models of Light Huygen couldn\'t help contradicting Newton and said that light is a wave since it spreads out at times.

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Models of Light Einstein understood that light demonstrations as waves as well as quantum particles now known as photons. Light has double properties – Particles and Waves

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An occasion skyline exists inside which the exceptional gravitational field of the dark opening keeps any kind of electromagnetic radiation including light from getting away Black Holes Question: Does light have mass? Once was a star at any rate double the mass of the sun that depleted its fuel and caved in to unending thickness

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An insatiable dark opening This is a Hubble Space Telescope picture of a 800-light expansive winding molded circle of tidy energizing an enormous dark gap in the focal point of cosmic system NGC 4261, found 100 million light-years away toward the heavenly body Virgo. By measuring the speed of gas whirling around the dark opening, space experts compute that the protest at the focal point of the circle is 1.2 billion circumstances the mass of our sun.

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Animated reenactment of gravitational lensing brought about by a dark opening going past a foundation cosmic system. http://en.wikipedia.org/wiki/File:BlackHole_Lensing.gif

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Speed of Light A. Roemer was the primary individual to attempt to gauge the speed of light in perceptions of Io . His figuring was 300,000 km/s.

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Speed of Light In 1880, Albert Michelson measured the speed of light to be 299,920 km/s. Utilized turning octagonal mirrors and a mirror far away Adjusted turning rate to compute speed of light In 1907, he won the Nobel prize in material science.

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Electromagnetic Wave Velocity Light could circumvent the world 7.5 circumstances each second http://liftoff.msfc.nasa.gov/institute/rocket_sci/satellites/geo-high.html

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Electromagnetic Wave Velocity Light takes 8 minutes to fly out from the sun to earth .

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Electromagnetic Wave Velocity The following nearest star is 4 light years away The distance across of our universe is 100,000 light years Some cosmic systems are 14 billion light years away http://bluepoint.egenet.net/sagan/galaxy.gif

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Electromagnetic Spectrum Energy moving at speed of light Vary by f and l just Light is just a little part Below light is infrared, above is bright

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Electromagnetic Spectrum Radio Waves – correspondence TV and Radio Microwaves –cooking & mobile phones Infrared – "warm waves" Visible Light – identified by your eyes Ultraviolet – causes sunburns X-beams – infiltrates tissue Gamma Rays – most enthusiastic

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The Visible Spectrum A scope of light waves reaching out in wavelength from around 400 to 700 nanometers Less than 1% of the whole range

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Questions Is it right to state that radio wave is a low-recurrence light wave? Is a radio wave additionally a sound wave?

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Transparent Materials Transparent - the term connected to materials through which light can go in straight lines

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Visible Light and Glass Visible light keeps up a similar recurrence when it enters glass But the speed changes: Light ventures 0.75x the first speed in water In glass – 0.67x. In jewel – 0.41x When the light turns out it recaptures its speed

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Opaque Materials Opaque - the term connected to materials that assimilate EM

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Opaque Materials Opaque materials retain EM ex.) wood, metal, rocks ,etc. The light vitality is changed into irregular active vitality makes the protest hotter in light of the fact that it ingests the electromagnetic vitality

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http://www.ch.ic.ac.uk/neighborhood/ventures/direct/chloro.htm

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Example Questions Are mists straightforward or hazy to noticeable light? Reply: hazy Are mists straightforward or murky to bright light? Reply: straightforward

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Example Questions Are windows straightforward or obscure to unmistakable light? Reply: straightforward Are windows straightforward or misty to bright light? Reply: misty Due to Law of Conservation of Energy the EM is emitted as warmth

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Shadows Umbra - the darker part of a shadow where all the light is blocked Penumbra - a fractional shadow These terms additionally apply to Solar Eclipses and Lunar Eclipses .

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Umbra Penumbra Solar Eclipse A sun powered overshadowing happens when the Moon goes before the Sun.

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A lunar overshadowing happens when the Moon goes into the Earth\'s shadow.

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Questions Which sort of overshadowing is hazardous to see with the unprotected eye? Why are lunar obscurations more usually observed than sun oriented shrouds?

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Seeing the Light – The Eye Cornea - does the majority of the centering Iris - has the eye shading and controls light force Pupil - the opening in the eye Lens - remainders of centering Retina - area of light sensors, has bars and cones focal point of vision, transcendently cones Fovea - Blind spot - optic nerve leave, no light sensors

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Parts of the Eye Detectors on the Fovea Rods light power and movement delicate Cones shading touchy The blind side for the eye is cause by the optic nerve .

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p. 474, Conceptual Physics 2002

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C o l o r V i s i o n ! Partial blindness - around 10% of the populace Red - green is transcendent Yellow-blue - a couple Total – some Mostly guys – X-connected attribute

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Color Deficiency

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Optical Illusions

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Optical Illusions

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Optical Illusions Are the even lines parallel, or do they slant?

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Optical Illusions

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Optical Illusions During the Optical Art (OpArt) Movement of the 1960s, craftsmen would make all kind of baffling impacts with shading. This "flashing squares" attracting appears to wobble and blaze when you focus on one specific region of the picture. What number of squares would you be able to find in this outline? Will you feel the "motion" of the picture?

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Optical Illusions

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Optical Illusions Can you number the dark spots?

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Optical Illusions

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Myopia (Near-Sightedness) People with partial blindness can\'t see unmistakably at separation.

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Hyperopia (Farsightedness) People with far-sightedness can\'t see plainly very close

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You will watch an aggregate overshadowing of the sun when... (a) you\'re in the penumbra of the moon\'s shadow (b) you\'re in the umbra of the moon\'s shadow (c) sunlight diffracts around the moon (d) sunlight reflects from the moon to the earth (b) you\'re in the umbra of the moon\'s shadow

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The speed of light... (a) has never been measured (b) is about the same as that of sound (c) is vastly quick (d) is quick, however not limitless (d) is quick, but rather not interminable

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oblivious in late night no shading is seen as a result of absence of incitement of a. bars. b. cones. c. cornea. d. crystalline focal point. b. cones.

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Self Test On a Blank Page.... List the Seven Forms of Light Which has the longest wavelength? Which has the most elevated recurrence Which has the most astounding vitality? Which has the speediest speed?

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Neutron Proton Electron Energy Levels or Orbits Structure of the Atom

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Ground State of Electron Energy level it typically possesses condition of most minimal vitality for that electron

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Excited State of Electron Temporarily vitality state more prominent than its ground state e - can get to be distinctly energized in the event that it is given additional vitality retains a photon, or parcel of light or slams into an adjacent molecule or molecule

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Emission of Photon Electrons don\'t remain in energized states for long they soon come back to their ground states discharging a photon with an indistinguishable vitality from the one that was assimilated

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Transitions among the different orbitals are extraordinary for every component on the grounds that the vitality levels are extraordinarily controlled by the protons and neutrons in the core

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When the electrons of a specific particle come back to bring down orbitals from energized states, the photons they transmit have energies that are normal for that sort of iota This gives every component a one of a kind unique finger impression, making it conceivable to distinguish the components exhibit in a holder of gas, or even a star

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Emission Spectrum Kirchhoff-Bunsen Experiment These two researchers found that copying chemicals over an open fire brought about an emanation range with splendid lines They found that every substance component created its own trademark example of brilliant unearthly lines

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Hydrogen Helium Oxygen Carbon Every component can be "fingerprinted" by it spectra.

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Continuous Spectrum Incandescence Hot, thick solids deliver a constant range .

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The shade of light radiated by a hot protest changes with its temperature most sultry sparkling item  Bluish White Yellowish Orange-ish coolest shining article  Reddish

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Absorption Spectrum Absorption Spectra Cool gas before a nonstop wellspring of light delivers an ingestion line range . Fraunhofer lines in our Sun\'s range demonstrated that cool helium gas encompasses the Sun.

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Matching Questions Type of Spectrum Appearance 1. Discharge Spectra a. All Colors 2. Consistent Spectra b. Dull Lines 3. Assimilation Spectra c. Splendid Lines

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Matching Questions

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