cahaya in english

8/3/2019 CAHAYA in English

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PELINDUNG ORANG-ORANG YANGBERIMAN. DIA MENGELUARKAN

MEREKA DARI KEGELAPAN MENUJUCAHAYA.

(QS 2:257)


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BASIC COMPETENCY

INVESTIGATING THE

PROPERTIES OF LIGHT ANDITS RELATION WITH

VARIOUS KINDS OF

MIRRORS AND LENS


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What is light? Everything that is pop out from a source

but not a substance is called RADIATION

Light, infrared, ultraviolet , all three are

radiation

Light can be seen, while infrared and

ultraviolet cant

Thats why, light is the name that given for

radiation that can be seen by human eyes


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THE PROPERTIES OF LIGHT1. The velocity is 3 X 108 m/s

2. Transverse waves

3. Electromagnetic waves

4. Has energy

5. Linear propagation

6. reflected7. refracted

8. disperse


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Propagation of light


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LIGHT DISPERSE


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1. The distance between earth sun is 150

million km for light to travel. Its meanslight need 500 seconds to reach earth

2. Light of the sun needs 360 seconds to reach

Venus, what is the distance of sun Venus?3. The distance of Mars sun is 1.52 times

the distance of earth sun. If the distance of

sun earth is 150 million km, how long

does light takes to propagate from sun to

Mars?


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Shadow and Image

Shadow (bayang-bayang) is the dark

area behind things Image (bayangan) is collection of

reflective rays and refractive rays.


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Two kinds of shadow (Bayang-bayang):

Bayang-bayang inti (Umbra) is the darkarea that doesnt receive light at all

Bayang -bayang tambahan (Penumbra) is

the dark area which still have little lightfrom light source


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Two kinds of image (bayangan): Real image

image which caught by screen or image

which formed from the cut ofreflected/refracted ray

Virtual image

image which cannot caught by screen orimage which formed from extension cut ofreflected/refracted ray


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Cahaya berupa titik


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Cahaya berupa benda


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LIGHT REF

LECTION

1. DIFFUSE REFLECTION

2. SPECULAR REFLECTION


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SPEC

ULAR DIREC

TION

happens if the stream of light falls

on the body that its surface issmooth and shiny, so the direction

of the light stream goes to certain

direction


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DIFFUSE REFLEC

TION

Happens if the stream of light falls

on the body which its surface isrough, so the stream of parallel

rays which fall on the body will be

reflected to every direction


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LAW OF LIGHT REFLECTION

Incident angle is equal to reflected angle(i=r)

Incident ray, normal line, reflected ray lieon one flat line

REFLECTION OF LIGHT


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Law of light reflection

Incident ray normal line reflected ray

x x

Incident angle reflected angle


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Reflection on FLAT MIRROR

The properties of flat mirror

Virtual image Upright

Same size with the body

Facing perverted

Distance of the body to the mirror equal todistance the image to the mirror


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Formation of image on flat mirror

Distance of the body = Distance of the image


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The composition of two flat mirror

The composition of two flat mirror will

produce more than one image, its depend

on the angle of those two flat mirror.

What is the relation between the amount of

image and the angle ?


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The magnitude of angle = 90o

How many image that form ?

900


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The amount of image that

produce in flat mirror which

organized angle determine by:

n = 360 - 1

360

360


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Reflection onC

ONC

AVE MIRROR

The properties of concave mirror:

1.Call as convergent mirror

2.Collect light or rays which reflect

3.Use in various device: reflector in

searchlight of car or flash light


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Main axisP F O

THREE PARTICULAR RAYS


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Main axisP F O



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IMAGE FORMATION in CONCAVE MIRROR

Three particular rays in concave mirror

1. Incident ray which is paralles to main axis of the

mirror will be reflected passing trough the focuspoint (F)

2. The incident ray passing trough the focus pointwill be reflected parallel to main axis

3. The incident ray passing trough the center pointof curvature of mirror P will be reflected backtrough that center point of curvature


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Main axisP F O

LIGHT REFLECTION IN CONCAVE MIRROR

The image form minimized, inversed and real


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Main axisP F O

Image form enlarged, inversed and real


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Main axisP F O

Image form enlarged, upright and virtual


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Main axisP F O

No image


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Main axisP F O

The image has the same size, inversed and real


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THE FORMATION OF AN IMAGE

OF A CONVEX MIRROR

The characteristics

of the image are:

Virtual

Diminished

Upright


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FORMULAS USED IN

SPHERICAL

MIRRORThe two formulasrelated to mirrorsboth concave and

convex are shown:So = the distance

from object tomirror

Si = the distancefrom image tomirror

Rssfss ioio

211atau

111!!

o

i

o

i

s

s

h

hm !!


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f = focal length

R = radius of curvature

h0

= the height of the object

hi = the height of the image


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MAIN AXISF O F


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MAIN AXISF O F

REFLECTION OF LIGHT IN


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MAIN AXISF O F

REFLECTION OF LIGHT INCONVEX MIRROR


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MAIN AXISF O F


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XERCISE


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XERCISE:. A NAIL STAND UP IN FRONT OF CONCAVE MIRRORWITH THE DISTANCE 6 CM, AND THE FOCAL LENGTH IS

4 CM , CALCULATEA. THE DISTANCE OF AN IMAGEB. THE MAGNIFICATION OF AN IMAGEC. MAKE THE PICTURE FORMED OF IMAGE

D. THE CHARACTERISTIC OF AN IMAGE. TWO PLANE MIRROR FORM AN ANGLE OF 30O TO EAC

OTHER. DETERMINE THE NUMBER OF THE IMAGE ?. AN OBJECT AT 18 CM IN FRONT OF CONCAVE MIRROR

WHICH RADIUS 12 CM. IF THE HEIGHT OF AN OBJECT IS3 CM. CALCULATE:A. THE DISTANCE OF IMAGE D. MAKE THE PICTUREB. THE HEIGHT OF IMAGE E. THE CHARACTERIST

C. MAGNIFICATION


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EXERCISE:

1. AN OBJEVT AT 180 CM IN FRONT OF CON, CALCULATEA. THE DISTANCE OF AN OBJECTB. THE MAGNIFICATION OF AN IMAGEC. MAKE THE PICTURE FORMED OF IMAGE

D. THE CHARACTERISTIC OF AN IMAGE


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