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

A PIECE OF

GLASS THAT

FORMS THE

SPECTRUM

PRISM

PRISM

• LIGHT BENDS AS IT ENTERS &

LEAVES BECAUSE THE SPEED OF

LIGHT CHANGES DUE TO A

CHANGE IN MEDIUMS

LENS

•ANY TRANSPARENT

MATERIAL THAT

REFRACTS LIGHT

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

CONCAVE LENSES ARE THICKER AT THE ENDS

COLOR

TRANSPARENT

• MATERIAL THROUGH WHICH

LIGHT IS EASILY TRANSMITTED

EX: GLASS, WATER, AIR

TRANSLUCENT

• A SUBSTANCE THAT

TRANSMITS LIGHT,

BUT NO DETAIL

EX: WAX PAPER, FROSTED GLASS

OPAQUE

• A SUBSTANCE THAT DOES

NOT TRANSMIT LIGHT

EX: BLOCK OF WOOD, SHEET

OF METAL, BLACK CLOTH

WHAT ABOUT IN GREEN OR BLUE LIGHT?

ALL COLORS ARE ABSORBED,

& NO LIGHT IS REFLECTED

WITH WHITE LIGHT ON A BLACK OBJECT

PRIMARY COLORS OF LIGHT VS. PRIMARY COLORS OF PIGMENTS

PAINTS ARE PIGMENTS

THEY’RE OPAQUE,

NOT SOURCES

OF LIGHT

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

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

HOW WE SEE

CONVEX LENS

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

OPTICAL INSTRUMENTS

CAMERAS

MICROSCOPES

TELESCOPES

LASERS

• A DEVICE THAT PRODUCES AN INTENSE

BEAM OF LIGHT OF ONE COLOR

•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

USES OF LASERS

MEASUREMENT

MEDICINE

THEY HEAL WHILE THEY CUT

INDUSTRY

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

HOLOGRAPHY

THE TECHNOLOGY THAT USES LASERS TO PRODUCE

3-D VIRTUAL IMAGES