REFRACTION OF LIGHT. REFRACTION THE BENDING OF LIGHT DUE TO A CHANGE IN ITS SPEED.
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Transcript of REFRACTION OF LIGHT. REFRACTION THE BENDING OF LIGHT DUE TO A CHANGE IN ITS SPEED.
• LIGHT TRAVELS AT A CONSTANT SPEED IN A
STRAIGHT PATH THROUGH A MEDIUM
• TRAVELS AT DIFFERENT SPEEDS WHEN IT CHANGES
MEDIUMS
• WHEN LIGHT PASSES AT AN ANGLE FROM ONE
MEDIUM TO ANOTHER, IT BENDS
• MORE DENSE THE MEDIUM = LIGHT SLOWS DOWN
(AIR TO WATER)
• LESS DENSE = LIGHT SPEEDS UP (GLASS TO AIR)
INDEX OF REFRACTION
• THE COMPARISON OF THE SPEED OF LIGHT IN
AIR WITH THE SPEED IN A CERTAIN MATERIAL
• IT’S A MEASURE OF HOW MUCH A RAY OF
LIGHT BENDS WHEN IT ENTERS THE MATERIAL
• EVERY MEDIUM HAS A SPECIFIC ONE
• THE LARGER THE INDEX OF REFRACTION, THE
MORE LIGHT IS BENT
MIRAGES
• A FLOATING IMAGE THAT APPEARS IN THE DISTANCE & IS DUE TO THE REFRACTION OF LIGHT IN THE
ATMOSPHERE
• HAPPENS DUE TO LARGE CHANGES IN
TEMPERATURE IN THE AIR
• LIGHT REFRACTS AND CAUSES A DISTORTED IMAGE
MIRAGES
• WHITE LIGHT = ALL VISIBLE COLORS
• EACH COLOR CORRESPONDS TO A PARTICULAR
WAVELENGTH
• EACH WAVELENGTH IS REFRACTED BY A DIFFERENT
AMOUNT
• THE LONGER THE WAVELNGTH, THE LESS BENDING
• RED HAS THE LONGEST WAVELENGTH SO IT’S
REFRACTED THE LEAST…CAUSES RAINBOWS
EM SPECTRUM
PRISM
• LIGHT BENDS AS IT ENTERS &
LEAVES BECAUSE THE SPEED OF
LIGHT CHANGES DUE TO A
CHANGE IN MEDIUMS
CONVEX LENS - CONVERGES
(BRINGS TOGETHER)
THE LIGHT RAYS
CONCAVE LENS - DIVERGES
(SPREADS OUT) LIGHT RAYS &
CREATES A VIRTUAL IMAGE
CONVEX LENSES ARE THICKER IN THE CENTER THAN AT THE EDGES
CONVERGING LIGHT RAYS
FOCAL POINT
SUBTRACTING COLORS
• WHEN THE 3 PRIMARY PIGMENTS
ARE MIXED EQUALLY,
ALL COLORS ARE ABSORED = BLACK
• BY MIXING MORE & MORE PIGMENTS, MORE
OF THE VISIBLE SPECTRUM IS ABSORBED
(SUBTRACTED) FROM WHAT WE SEE
POLARIZED LIGHT
• LIGHT IN WHICH ALL THE WAVES ARE
VIBRATING IN THE SAME DIRECTION
• THE GLARE OF SUNLIGHT IS MOSTLY
HORIZONTAL SO SOME SUNGLASSES ARE
VERTICALLY POLARIZED TO REDUCE GLARE
NEARSIGHTED FARSIGHTED
• EYEBALL TOO LONG
• HARD TO SEE AT A
DISTANCE
• LENS IS TOO CONVEX SO
RAYS CONVERGE IN FRONT
OF RETINA
• CORRECT BY USING
CONCAVE LENS TO MAKE
RAYS DIVERGE BEFORE
ENTERING EYE
• EYEBALL TOO SHORT
• HARD TO SEE CLOSE UP
• LENS IS NOT CONVEX
ENOUGH SO RAYS
CONVERGE BEHIND RETINA
• CORRECT BY USING CONVEX
LENS TO MAKE RAYS
CONVERGE BEFORE
ENTERING EYE
•LIGHT IS ONLY ONE WAVELENGTH
•ALL THE WAVES TRAVEL IN STEP
(ALL CRESTS NEXT TO
EACH OTHER ETC.)
•LIGHT INTENSITY IS NOT REDUCED
BECAUSE LIGHT DOESN’T SPREAD
•CALLED COHERENT LIGHT
FIBER OPTICS
LONG, THIN STRANDS OF GLASS OR
PLASTIC THAT CARRY LIGHT FOR
LONG DISTANCES WITHOUT FADING
• TRANSMIT SIGNALS AS FLASHES OF LIGHT
• CAN CARRY MORE INFORMATION THAN RADIO
WAVES BECAUSE OF HIGHER FREQUENCY
• LASER LIGHT CAN TRAVEL THROUGH THE CURLED
UP OPTICAL FIBER BECAUSE IT IS BENT SO MUCH
THAT IT’S REFLECTED = THIS IS CALLED
“TOTAL INTERNAL REFLECTION”
FIBER OPTICS