Aim: How can we explain polarization and dispersion? Do Now: Why do athletes wear polarized...
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Transcript of Aim: How can we explain polarization and dispersion? Do Now: Why do athletes wear polarized...
Aim: How can we explain polarization and dispersion?
Do Now:
Why do athletes wear polarized sunglasses?
Incoherent Light• When light waves emitted by a
source have no special phase relationship, the light beam spreads and loses intensity quickly
Coherent Light
• Monochromatic light with most waves in phase, spreads very little and is intense
• A laser!!
• Light coming from the sun or a light bulb emit light waves that are vibrating in every plane
• We call this type of light unpolarizedunpolarized
Polarized Light• A beam of light that only
vibrates in one direction
So what happens if we add a 2nd polarizing filter oriented 90° to the 1st?
Demo
What’s Happening?
• Only transverse waves (like light) can be polarized
• Can sound waves be polarized?
NO!!!
Dispersion• When polychromatic (white) light is
passed through a prism, it is separated into its component colors
What is Polychromatic Light?
• Which light bends the least?
• Which light bends the most?
redred
violetviolet
Why?Speed of light inside prism depends on
the wavelength of light
v = fλ (f is const!!)
λred = highest
vred = highest
Red has the lowest index of refraction, therefore bends the least
Violet therefore bends the most
Dispersive Mediums
• Prisms• Air (rainbows)• Glass
Thin films of:– Water– Bubbles– Oil– Gas
• People?
Prism Spectrometer
• Disperses light into component colors
• Allows you to determine the elements the stars are made out of when attached to a telescope
Gas Tubes