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physics: light

Terms in this set (74)

electromagnetic waves consist of ___
changing magnetic and electric fields moving thru space @ the speed of light
what's the speed of light?
3.0 * 10^8 m/s
electromagnetic waves are produced by ___
vibrating charged particles
Electromagnetic waves do not require a ____
medium
The electromagnetic spectrum is a range of ___
freq of electromagnetic waves
In the electromag. spectrum, as __ increases ___ decreases
freq, wavelength
In the electromag. spectrum as ___ increases, the ___ of the wave increases
freq, energy
Waves in order?
radio, microwave, infrared, visible, uv, x-rays, gamma rays
Radio waves have the lowest ___ and the longest ___
freq, wavelength
Radio waves also include ___ waves
TV, UHT, and Radar
Radio waves are also called ___ waves
carrier
Microwaves have no effect on ___
plastics, ceremics, or glass
Infrared waves: ___ and reg size ___ vibrate to prod. infrared waves
large, molecules
all objects emit infrared waves in the form of ___
heat
visibile light is electromag radiation to which ___ are sensitive
eyes
visible lights makes up less than ____ of electromag. spectrum
10^-1 %
In visible light, diff freq are seen as ___
colors
In visible light, red has the ____ and ___ energy, and violet has the ____ and energy
lowest, highest
UV can cause
skincancer and sunburn
X-rays were discovered by ___
rentin
X-rays are produced by the greatest acceleration of ___
atoms and electrons
Gamma rays have the highest __ and greatest ___ power
energy, penetrating
Gamma Rays are produced by ___ reactions , includ. decay of ___ atoms and nuclear explosions
nuclear, radioactive
Gamma rays kill ___ cells before it kills ___ cells
cancer, healthy
Gamma rays can be used for ___
MRI'S
Xrays can be used to see ___
bones
Whats the photoelectric effect?
light produces electricity
Violet and uv light ___ eject electrons but red light ___ works
always, never
when the photoelectric effect occurs, it does so _____, there is never a ___ delay, even with the ___ light
immediately, time, faintest
Bright light ejects ____ electrons, but their ____ ___ depends on the __ of light, not the ____
more, ____, freq, speed
The quantum theory ___ to explain the photo electric effect
used
What's evidence for the wave nature of light ?
It reflects & obeys laws of reflection, light refracts, light diffracts around objects
when certain freq of light shine on a metal surface __ are ejected
electrons
W or P ? when light goes thru a single slit, it spreads out.
wave
w or p ? when some colors of light shine on a metal plate, electrons are ejected.
particle, photoelectric
w or p ? only cer. colors of light cause photosynthesis
particle
w or p ? when light moves from air to water, it bends
wave, refraction
w or p ? when light goes thru to narrow slits, a pattern of dark and bright regions shows on the screen.
wave , interference
w or p ? when gaseous atoms are bombarded with electricity , certain colors of light are produced
particle
Whats uses for the photoelectric effect?
night lights, alarm systems, solar calculators
Who developed quantum theory ?
max planck
Who used quantum theory to explain photoelectric effect ?
einstein
formula for calculating energy of a photon of light ?
e=hf
why does bright red light nvr produce p.e.e ?
because red light doesnt have enough energy to eject electrons when absorbed by atoms
Whats the quantum theory ?
energy is radiated and absorbed in tiny indivisible bundles, each packet i called a quantum, a quantum of light is called a photon, the energy of photon depends on freq, each electron can absorb single photon light
Evidence for particle nature of light ?
only certain freq can prod photosynthesis, red lights are used in dark rooms and do not effect chemicals
Modern light theory called ?
wave particle duality
Light moves thu spaces as a ___ and interacts with matter as a ____
wave, particle
an illuminated body ___ light waves
reflects
a luminous body ___ light waves
emits
How is light produced ?
Fusion reacts on sun, incandescence, gas discharge tubes, fluorescence, chemo-luminescence, bio-luminescence
LASER stands for ?
light amplified by stimulated emission of radiation
Coherent light is ___ and consists of ____ waves in phase, and amplified by ______ . It forms an ____ narrow _____
monochromatic, identical, constructive interference, intense, beam
____ made a device that prod stimulated emission
gordon gould
A prism sep. ___ into the ___ of the visible spectrum
white light, components
the color of an object depends on ___
colors of light reaching the day
why does a green leaf look green ?
it reflect green portion of spectrum in our eyes
__ reflects all colors and we see it if no freq of light are absorbed
white
___ reflects no colors and we see it if all freq of light are absorbed
black
primary colors are ___ chromatic
poly
colors are beams of __
light
primary colors are called ____ colors
additive
Three primary colors ?
red, green, blue
secondary colors ?
magenta, yellow , cyan
Pigments are chemicals that ___ certain ___ of light and ___ or ___ others
absorb, freq, reflect, transmit
primary pigments are ___ pigments
subtractive
the spreading of light waves when they go thru a narrow slit is ___
diffraction
light waves show ___ patterns when they go thru a double slit
interference
LASER invented in 1950s based on ___
Einstein
Facts about light expl. by quantum theory : ___ of colors by __ electrons, __ reactions that are prod by certain ___ of light ___ by chemicals
emission, excited, freq, absorbed
Four words to describe laser light
coherent, monochromatic, intense narrow beam
Why is wave particle duality the modern theory o flight ?
neither wave nor particle can explain all prop of light
First laser Describe :
ruby crystal with a tube wrapped around it and mirrors at the end, one partial
A pigments absorbs its ___
compliment
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