Photo from Wikipedia
Grass
Parking lot
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v f 5
the peaks in the waves.
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A simple model of light changing medium
into the cond medium. Simulation
Partially reflected r清淡
ay
Partially refracted ray
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Snell’s Law (Cont’d)
The angle of refraction 2(the angle in the cond medium) is related to the angle of incidence 1by
n 1is the index of refraction of the first medium and n 2is the index of refraction of the cond medium. Angles are measured形容老人的词语
from the normal , which is the line
perpendicular to the interface.
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Snell's Law: sin sin n n =n 1n 2
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Toward/away from the normal
When light cross an
interface into a medium with a higher index of refraction (e.g. air to water), the light bends toward the normal.
Converly, light traveling across an interface from higher n to lower n (e.g. water to air) will bend away from th重庆交通大学是几本
e normal.
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Refraction in a rectangular block
A beam of light traveling in air enters a rectangular glass
block. Assuming the light exits the block along the side opposite to the side it entered, what path does the light follow when it emerges from the block? 1. The exact path it was following when it entered the block.
2. A path parallel to the original path, but displaced from it.
3. A path perpendicular to the original path.
4. None of the above.
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Air to glass:
Glass to air:
Reflected rays
Refracted rays
Refracted rays
Reflected rays
Note that the refracted light rays are confined in a cone defined by the refraction angle of an incoming ray with incident angle = 90o .
What happen when we incident light from glass with an angle outside this cone?
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reflected 16
bouncing back and forth as it makes its way along.
Photo + diagram from Wikipedia
, , and the angle of incidence in
medium 1 is the critical angle for total , and the angle of incidence in
mediu武侠小说排行榜前十名
m 1 is the critical angle for total
n 1
Incident ray
into all the colors of the rainbow. Why is this?
Figure from Wikipedia
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bent) more than the red (700 nm) end, with all the Wavelength, (m)
R e f r a c t i v e i n d e x , n
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Rainbows
Light refracts into spherical water droplets in the sky, reflects once off the back of五豆豆浆
the droplet, and then refracts back out into the air. There is some dispersion, so the different colors refract at different angles. Red light is refracted (bent) less than other colors. So for an obrver at a fixed position, red light is en to be scattered from droplets higher in the sky than droplets scattering light of other colors.
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Co阳光怎么形容
nvex lens
Concave lens
Convex lens bend an incoming ray toward the principal axis while concave lens bend it away (except for ca 3). Thus, convex lens are convergent lens and concave lens are divergent lens. Note that you get two focal points with lens!
