51 LIGHT Refraction

8/7/2019 51 LIGHT Refraction

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5.2 REFRACTION

REFRACTIONINDEX LENSES

CONCAVELENS

CONVEXLENS


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How d oes th e ph enomenon c oul d happ en?

Watch thi s vid eo:

Ve di o


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Obj e ct Phy s ic s

Im ag e

Th e ray fr om o bj e ct pa sses thr ou gh a g la ss in to air

is b en t a w ay fr om th e NORMAL

b e ca use th e g la ss is d ense r tha n th e air

Th e ray ha s b een REFRACTED

Th e Answe r :

No r m a l


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REFRACTION OF LIGHT

In cid en tray

No r m a l

Re fract e dray

i

r

AIR

GLASS

GLASS

AIR

Light ray s b en dtow ard s th e no r m a l

Light ray s b en d a w ayfr om th e no r m a l

3. Why ?

Gla ss is d ense r tha n air

4. What ar e th e variab les that ar e

cha n g e w h en th e lightpa sses thr ou gh adiff e r en t me di um?

i. Th e dir e cti ons

ii. (Velo city)

iii. ( Wav e len gth)

1. How th e lightmo ves fr om th e air thr ou gh th e g la ss?

2. How th e lightmo ves fr om th e g la ss thr ou gh th e air ?


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a) What is your inference?b) Stat e one app ropriat e hypothesis that could be inves teg at ed.

c) P la n one ex perimen t to inves tigat e the rel at ions hip be tween twova ria bles that refer to your hypothesis.d) Write a com ple te re por t.

In you r r e p o rt d es crib e c le ar ly th ese items,

Th e ai m o f th e ex p e rimen t:Th e variab les: (Ma n ip ul at e d , r es p on di n g a n d fi xe d)

Lis t a c om p le te apparat us a n d dra w th e arra n g emen t

Writ e th e pr o c e d u r e o f a n ex p e rimen t in c lu d es th e s te p on h ow to g e tmo r e acc u rat e data

Tab ul at e th e data

Dra w a Graph o f s in i v s s in r a n d ca lc ul at e th e GRADIENT

Writ e th e Con c lus ion fr om a graph a n d s tat e th e r el ati ons hip b e tween GRADIENT a n d R e fractiv e In d ex o f me di um


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i = 25 o , 20 o , 15 o , 10 o , 5o

i

Re f e r thi s s te p s to w rit e th e pr o c e d u r e o f ex p e rimen t

Pap e r

P en ci l

Gla ss Blo ck

Pr o tract o r

Ray b ox


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7

10 o

i

5o

15 o

20 o

25 o

r

No r m a l

io r o Si n io Si n r o

5

1015

20

25

Si n i

Si n r


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Refr a ctive Index, nn = s in i (vacuum) > K nown a s S nells La w

s in r (medium)

Si n i

Si n r

0 0.5 1.0

0.5

1.0Dia mon d

Gla ss

Wat e r Material Refractive

Index, n

Diamond 2.42

Glass 1.5

Water 1.33

TheEffect:

Bendingof lightGreater

Smaller


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Exa m p les:Ca lculat e the refr a ctive index, nof the follo wing;

n = s in (vac uum@ air)s in (me di um )

= s in 48/ s in 15= 2.87

n = s in (vac uum@ air)s in (me di um )

= s in 60/ s in 40= 1. 35

42 o

15 o

30o

50 o

P e r s p ex

Air Air

Gla ss


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51 LIGHT Refraction