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Light (simply). A Simple Review for Complex Seniors. EM Radiation. Light is caused by high energy electrons that move from higher energy shells to lower energy shells. The bundle of energy that they give off is called a “photon”. Photons travel through a vacuum at 3x10 8 m/s. model. - PowerPoint PPT Presentation
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Light (simply)Light (simply)
A Simple Review for Complex Seniors
A Simple Review for Complex Seniors
EM RadiationEM Radiation
Light is caused by high energy electrons that move from higher energy shells to lower energy shells. The bundle of energy that they give off is called a “photon”.
Photons travel through a vacuum at 3x108 m/s
Light is caused by high energy electrons that move from higher energy shells to lower energy shells. The bundle of energy that they give off is called a “photon”.
Photons travel through a vacuum at 3x108 m/s
model
Sources of LightSources of Light
Luminous sources are objects that emit light waves . The sun is a luminous body.
Illuminated objects reflect or transmit light that is incident upon them. The Moon is an illuminated body.
Transparent - transmits light Translucent - transmit, but reflects some light. Opaque - reflects all light
Luminous sources are objects that emit light waves . The sun is a luminous body.
Illuminated objects reflect or transmit light that is incident upon them. The Moon is an illuminated body.
Transparent - transmits light Translucent - transmit, but reflects some light. Opaque - reflects all light
Quantity of LightQuantity of Light
The rate at which energy is emitted from a luminous body is called the luminous flux. (P)
Measured in lumen. (lm) A 100W light bulb emits 1750 lumen.
The rate at which energy is emitted from a luminous body is called the luminous flux. (P)
Measured in lumen. (lm) A 100W light bulb emits 1750 lumen.
Inverse-Square RelationshipInverse-Square Relationship
Luminous IntensityLuminous Intensity
The flux that falls on 1m2 of the inside of a 1 meter radius sphere.
Intensity is flux/4π and is measured in candela, (cd).
The flux that falls on 1m2 of the inside of a 1 meter radius sphere.
Intensity is flux/4π and is measured in candela, (cd).
Ray Model of LightRay Model of Light
These photons travel in straight line paths. Used to demonstrate the ways that light
interacts with other objects.
These photons travel in straight line paths. Used to demonstrate the ways that light
interacts with other objects.
Wave-Particle DualityWave-Particle Duality
Christiaan Huygens- Dutch (1629-1695) presents a “wave model of light” to explain
diffraction patterns.
Newton- English (1643-1727) presents a “corpuscle (particle) model of light”
in competition.
Christiaan Huygens- Dutch (1629-1695) presents a “wave model of light” to explain
diffraction patterns.
Newton- English (1643-1727) presents a “corpuscle (particle) model of light”
in competition.
Light as a WaveLight as a Wave
Thomas Young’s Double Slit Experiment Thomas Young’s Double Slit Experiment
James Maxwell: studied other electromagnetic waves: Suggested light was an EM wave Results confirmed.
James Maxwell: studied other electromagnetic waves: Suggested light was an EM wave Results confirmed.
Light as a ParticleLight as a Particle
Albert EinsteinAlbert Einstein
Wins Nobel prize for explaining that light is a particle AND a wave at the same time.
States that light is carried in packets of different energies. Called quanta.
Blue has more energy than red no matter the intensity. Why electrons are ejected for blue but not red.
Wins Nobel prize for explaining that light is a particle AND a wave at the same time.
States that light is carried in packets of different energies. Called quanta.
Blue has more energy than red no matter the intensity. Why electrons are ejected for blue but not red.
RGBY?!?!?!? WHY!?!?!They are counting on you
to be stupid!
RGBY?!?!?!? WHY!?!?!They are counting on you
to be stupid!
ColorColor
Color works by absorption or reflection of specific wavelengths of light.
Green objects reflect green light and absorb all others. Magenta objects absorb all green and reflect blue and red.
Color works by absorption or reflection of specific wavelengths of light.
Green objects reflect green light and absorb all others. Magenta objects absorb all green and reflect blue and red.
How about the weird stuff?How about the weird stuff?
Shine red light on a green object. What do you see?
A.) red. B.) green C.) orangey greenish D.) black
Shine red light on a green object. What do you see?
A.) red. B.) green C.) orangey greenish D.) black
Why?Why?
GUMMY BEARS AND LASERS!
