Unit 1 Flashcards
Christian Huygens (1629-1695)
Wave theory of light, lights waves. Mathematician
Sir Isaac Newton (1642-1726)
Corpuscular theory of light, light is emitted by tiny particles called corpuscles
James Clerk Maxwell (1831-1879)
Electromagnetic theory of light
Leon Foucault (1819-1868)
Made measurement that accurately measure the speed of light
Max Planck (1858-1947)
Planks constant, which defines the quantum energy of photons when their frequency is known, light travels as photons
Albert Einstein (1879-1955)
Theory of relativity
Wave theory of light
1) wavelength in nm
2) frequency (f) in unit Hertz (Hz)
3) Speed of light (v) = 3.00x10^8
Frequency
Frequency = speed/wavelength
Electromagnetic spectrum
Ordered
- gamma rays
-X-ray
-ultraviolet
-visible light
-infrared
-microwave
-radio waves (fm,am)
-long radio waves
Units of illuminamce
Lux(lx) — measurement of the intensity of light
— luck is one lumen per square meter area
Luminous flux
Quantity of energy of light emitted per second in all directions
Lumens
Unit
Luminous flux
Objective measure of the useful light emitted by a light source is often used as an objective measure. Typically reported on the packaging for light bulbs.
Foot candle
1 foot away, unit of illuminance equal to one lumen per square foot
Geometric Optics
1) branch of optics dealing with light rays
2) study of the effect of mirror and lenses on light rays
Conventions of light rays
1) travel form left to right
2) travel away from the source
3) can be acted upon by mirrors, lenses, prisms
Reflection of light
How light reflects off surfaces
Light rays — Diverging
Moving outward, minus power, concave
Light rays — Converging
Coming to you, plus power, convex
Parallel (zero vergence)
Light rays parallel to each other due to no vergence
Images — real
On the left = real
Virtual
On the right
Type of image depends on
- specific type of mirror
-where the object is placed
Concave mirrors (converging)
Real, inverted, smaller
Convex mirror (diverging mirror)
Virtual, upright, smaller image
Index of refraction
How much the path of light is bent or refracted. Light bends moving from less dense to more dense.
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