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· Can be a wave transporting energy
· Can be a stream of particle |
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– 1st accurate measurement of speed of light by observing Jupiter’s moons.
· When Jupiter was farther from the earth it too 15 minutes later.
· Divided difference in distance (closest & farthest point) by 15 |
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– used rotating saw toothed wheel to get a more precise measurement.
11-2 Light can be a wave. |
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| -if light is a wave it will: |
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· Reflect – your image on a mirror
· Refract – stick looks bent in water
· Diffract- light spot emerging from the smallest hole in a sheet of metal spreads out the most.
· Interference – “double-slit experiment” by Thomas Young
o light from a single slit diffracts to either side of it. –
o Light from 2 slits diffracts and interferes creating a series of bright lines (constructive interference) and dark lines (destructive interference).
· Diffraction grating – separates light into its component colors by means of interference. |
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| – thought to be a substance that filled all of space. |
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| – quantities existing at every point in the space where the field is present. Like temperature in a room. |
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· A set of four fundamental laws, expressed in mathematical form, that govern electricity and magnetism and their inter-relationship. The Electrical force law is included in Maxwell’s Equations.
· Predict strength and direction of the electromagnetic field at any location in space.
· Helps us understand :
o shapes of fields
o strengths of forces within the fields
o how fields change when charges move.
· Predict waves and their speed (which is speed of light) |
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| Electromagnetic Radiation |
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Radiation originating in varying electromagnetic field, such as visible light, radio waves, x-rays and gamma rays.
· Electromagnetic waves radiate = electric charge accelerates |
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o Color depends on wavelength
§ red = longer wavelengths and lower frequencies
§ blue = shorter wavelengths and higher frequencies |
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· The ejection of electrons from metals when light is shined on the metal’s surface.
· Light is associated with frequency.
-shows that light acts like a particle. |
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· A particle of light
· It possesses energy, frequency and wave-length but not mass or charge.
Energy = h x frequency |
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· A value when multiplied by the frequency of light gives the energy of the photon of light at that frequency.
· Each photon caries an amount of energy proportional to its frequency
· Double frequency = double energy
Energy = h x frequency |
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The state of possessing both wave and particle properties.
· Light = stream of particles arriving at locations predicted in a probabilistic fashion from the wave model
· Tells us how light is detected
· The wave part tells us how photons travel and where they will be detected. |
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