# Shared Flashcard Set

## Details

Chapter 11
The Properties of Light
13
Physics
09/30/2010

Term
 Light
Definition
 · Can be a wave transporting energy· Can be a stream of particle
Term
 Roemer
Definition
 – 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
Term
 Fizeau
Definition
 – used rotating saw toothed wheel to get a more precise measurement.11-2 Light can be a wave.
Term
 -if light is a wave it will:
Definition
 · 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 Youngo 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.
Term
 Luminifer ether/ether
Definition
 – thought to be a substance that filled all of space.
Term
 Fields
Definition
 – quantities existing at every point in the space where the field is present. Like temperature in a room.
Term
 Maxwell’s Equations
Definition
 · 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 fieldso strengths of forces within the fieldso how fields change when charges move.· Predict waves and their speed (which is speed of light)
Term
Definition
 Radiation originating in varying electromagnetic field, such as visible light, radio waves, x-rays and gamma rays.· Electromagnetic waves radiate = electric charge accelerates
Term
 Visible light
Definition
 o Color depends on wavelength § red = longer wavelengths and lower frequencies § blue = shorter wavelengths and higher frequencies
Term
 Photoelectric Effect
Definition
 · 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.
Term
 Photon
Definition
 · A particle of light· It possesses energy, frequency and wave-length but not mass or charge.Energy = h x frequency
Term
 Planck’s Constant (h)
Definition
 · 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 energyEnergy = h x frequency
Term
 Wave-Particle Duality
Definition
 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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