electromagnetic waves h

8/10/2019 Electromagnetic Waves h

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Around 1820, a Danish physicist called Hans Christian Oersted (17771851) shoed that

an electric ire can create a pattern o! "a#netis"$ Decade later, %n#lish che"ist &ichael

'araday (171187) pro*ed that the opposite could happen too$ He pro*ed e can use

"a#netis" to #enerate electricity and that #i*e hi" to de*elop the electric "otor and electricity

#enerator that no e use in our orld$

Another #reat scientist, +a"es Cler &a-ell (18.1187) as a/le to co"e up ith a

onder!ul sin#le theory that e-plained /oth electricity and "a#netis"$ &a-ell su""ed up

e*erythin# people had disco*ered in !our si"ple euations to produce a super/ theory o!

electro"a#netis", hich he pu/lished in 187.$ He realied that electro"a#netis" could tra*el in

the !or" o! a*es, at the speed o! li#ht, and concluded that li#ht itsel! had to /e a ind o!

electro"a#netic a*e$ A/out a decade a!ter &a-ells death, a /rilliant 3er"an physicist na"ed

Heinrich Hert (1857184) /eca"e the !irst person to produce electro"a#netic a*es in a

la/oratory$ hat piece o! or led to the de*elop"ent o! radio, tele*ision, and "uch "ore

recently, thin#s lie ireless 6nternet$

%lectro"a#netic a*es are a*es that produced /y the si"ultaneous *i/ration and

oscillation o! electric or "a#netic !ield$ hey trans!er ener#y !ro" one place to another and they

can tra*el throu#h a *acuu"$ All electro"a#netic a*es are in*isi/le$ Hoe*er, the only

electro"a#netic a*es e can see is the *isi/le li#ht a*es$ %lectric and "a#netic !ields in

electro"a#netic a*es oscillates at ri#ht an#les to each other and to the direction o! tra*el$ 6t is a

trans*erse a*es and tra*el at the speed o! li#ht (. ) in *acuu"$ %lectro"a#netic

a*es posses a*es properties lie re!lection, re!raction, di!!raction and inter!erence$ 6t carries

no char#e (neutral)$ 9a*e euation ( is applica/le$ he !ull ran#e o! electro"a#netic

a*es, arran#ed orderly in their a*elen#ths and !reuencies is called the electro"a#netic

spectru"$ he electro"a#netic spectru" ran#es !ro" #a""a rays (ith the shortest a*elen#th)

to radio a*es (ith the lon#est a*elen#th)$

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http://www.explainthatstuff.com/radio.htmlhttp://www.explainthatstuff.com/television.htmlhttp://www.explainthatstuff.com/wirelessinternet.htmlhttp://www.explainthatstuff.com/radio.htmlhttp://www.explainthatstuff.com/television.htmlhttp://www.explainthatstuff.com/wirelessinternet.html


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Dia#ra" 1

he shortest a*e len#th is 3a""a rays ith "eters$ 6t is a sie o! ato"ic nuclei

and cannot penetrates earth at"osphere$ 6t has a !reuency o! 3a""a rays "ostly uses

!or ill cancer cells, sterilies "edical euip"ents and !oods$ :e-t, ;


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and relati*ely the sie o! protooan$ >isi/le li#ht *ery help!ul in photosynthesis o! plants and o!

course !or *isi/ility$ 'urther"ore, in!rared has a*elen#th o! "eters and !reuency o!

6t "ainly cannot penetrates earth at"osphere and relati*ely the sie o! pinpoint$

6n!rared use!ul in re"ote controllers, ca"eras, security alar"s and etc$ ?esides that, "icroa*e

has a*elen#th o! "eters and !reuency o! 6t "ainly cannot penetrates earth

at"osphere and relati*ely the sie o! honey/ee$ &icroa*es is !all under @adio a*es$ astly, is

@adio a*es$ @adio a*es has *ariety o! types such as lon# a*e uses in lon#


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The four electromagnetic waves which is I come in contact daily life in Malaysia is X-Rays,

Visible light, Infrared and Radio waves

X -RAY

hou#h they are "uch hi#her in !reuency than *isi/le li#ht, ith a*elen#ths a/out

1,000 ti"es shorter than !or ordinary li#ht rays$ ;< rays are a !a"iliar part o! current "odern li!e

due to their uses in "edicine$ 3er"an scientist 9ilhel" @ont#en (1845


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are used to photo#raph /ones and internal or#ans, and pro*ided the patient does not recei*e

prolon#ed e-posure to the rays, they cause little da"a#e$ Hard -< rays, on the other hand, are

desi#ned precisely to cause da"a#e$ :ot to the patient, /ut to cancer cells$ ?ecause they use hi#h

*olta#e and hi#h

handled ith proper procedure$

"T!$R A++'I&ATI"(*

;


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Dia#ra" 2

Visible 'ight

>isi/le li#ht a*es are the only electro"a#netic a*es e can see$ >isi/le li#ht has

a*elen#th o! "eters and !reuency o! 6t can penetrates earth at"osphere

and relati*ely the sie o! protooan$ 9e see these a*es as the colors o! the rain/o$ %ach color

has a di!!erent a*elen#th and !reuency$ @ed has the lon#est a*elen#th and *iolet has the

shortest a*elen#th$ 9hen all the a*es are seen to#ether, they "ae a hole hite li#ht$

9hen hite li#ht shines throu#h a pris", the hite li#ht is /roen apart into the colors o! the

*isi/le li#ht spectru"$ 9ater *apor in the at"osphere can also /rea apart a*elen#ths creatin#

a rain/o$

Dia#ra" 2

6


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Cones in our eyes are recei*ers !or these tiny *isi/le li#ht a*es$ hen, e can see a

spectru" o! colors hen e see$ his can di!!erentiate thin#s one another$ he un is a natural

source !or *isi/le li#ht a*es and our eyes see the re!lection o! this sunli#ht o!! the o/Bects

around us$ he color o! an o/Bect that e see is the color o! li#ht re!lected$ All other colors are

a/sor/ed$ i#ht /ul/s are another source o! *isi/le li#ht a*es$

>isi/le li#ht is *ery use!ul !or *isi/ility$ 9e can see o/Bects and al on our on$ 9e

can sense the en*iron"ent$ 9e can do all sort o! acti*ities such as cli"/in#, alin#, runnin#,

Bu"pin#, tra*elin# and "uch "ore$

&alaysia is a onder!ul country settin# in tropical arena$ 9e ha*e a lot o! di!!erent and

uniue plantation in the orld$ he i"portant process o! the plant is photosynthesis$

Ghotosynthesis a/sor/s car/on dio-ide and ater$ hen ith a help o! sunli#ht (*isi/le li#ht), the

plant produce starch and /y


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%iagram

Infrared

6n!rared li#ht lies /eteen the *isi/le and "icroa*e portions o! the electro"a#netic

spectru"$ 6n!rared li#ht has a ran#e o! a*elen#ths, Bust lie *isi/le li#ht has a*elen#ths that

ran#e !ro" red li#ht to *iolet$ :ear in!rared li#ht is closest in a*elen#th to *isi/le li#ht and

!ar in!rared is closer to the "icroa*e re#ion o! the electro"a#netic spectru"$ he lon#er, !ar

in!rared a*elen#ths are a/out the sie o! a pin head and the shorter, near in!rared ones are the

sie o! cells, or are "icroscopic$

'ar in!rared a*es are ther"al$ Heat is the in!rared radiation, e e-perience e*ery day

hich is a ther"al a*e $ he heat that e !eel !ro" sunli#ht, a !ire or li#ht, a radiator or a ar"

sideal is in!rared$ Our sin has the te"perature


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uses a siliconphotodiode to con*ert the in!rared radiation to an electric current$ 6t responds only

to the rapidly pulsin# si#nal created /y the trans"itter, and !ilters out sloly chan#in# in!rared

radiation !ro" a"/ient li#ht$ 6n!rared co""unications are use!ul !or indoor use in areas o! hi#h

population density$ 6@ does not penetrate alls and so does not inter!ere ith other de*ices in

adBoinin# roo"s$ 6n!rared is the "ost co""on ay !or re"ote controlsto co""and appliances$

6n!rared re"ote control protocols lie@C


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Radio #aves

Radio wavesare a type o! electro"a#netic radiation ith a*elen#ths in the electro"a#netic

spectru"lon#er than in!raredli#ht$ @adio a*es ha*e !reuencies!ro" .00 3Hto as lo as

. H, and correspondin# a*elen#ths ran#in# !ro" 1 "illi"eter to 100 ilo"eters$ As other

electro"a#netic a*es, they tra*el at the speed o! li#ht$ :aturally occurrin# radio a*es are

"ade /y li#htnin#,or /y astrono"ical o/Bects$ Arti!icially #enerated radio a*es are used !or

!i-ed and "o/ile radio co""unication, /roadcastin#, radar and other na*i#ation syste"s,

co""unications satellites, co"puter netors and innu"era/le other applications$ Di!!erent!reuencies o! radio a*es ha*e di!!erent propa#ation characteristics in the %arths at"osphereF

lon# a*es "ay co*er a part o! the %arth *ery consistently, shorter a*es can re!lect o!! the

ionosphereand tra*el around the orld, and "uch shorter a*elen#ths /end or re!lect *ery little

and tra*el on a line o! si#ht$

o pre*ent inter!erence/eteen di!!erent users, the arti!icial #eneration and use o! radio a*es

is strictly re#ulated /y la, coordinated /y an international /ody called the 6nternational

eleco""unications =nion(6=)$ he radio spectru" is di*ided into a nu"/er o! radio /ands

on the /asis o! !reuency, allocated to di!!erent uses$

he study o! electro"a#netic pheno"ena such as re!lection, re!raction, polariation,

di!!raction, and a/sorptionis o! critical i"portance in the study o! ho radio a*es "o*e in !ree

space and o*er the sur!ace o! the %arth$ Di!!erent !reuencies e-perience di!!erent co"/inations

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http://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Wavelengthshttp://en.wikipedia.org/wiki/Electromagnetic_spectrumhttp://en.wikipedia.org/wiki/Electromagnetic_spectrumhttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Frequencieshttp://en.wikipedia.org/wiki/GHzhttp://en.wikipedia.org/wiki/KHzhttp://en.wikipedia.org/wiki/Speed_of_lighthttp://en.wikipedia.org/wiki/Lightninghttp://en.wikipedia.org/wiki/Radio_astronomyhttp://en.wikipedia.org/wiki/Radio_communicationhttp://en.wikipedia.org/wiki/Broadcastinghttp://en.wikipedia.org/wiki/Radarhttp://en.wikipedia.org/wiki/Communications_satellitehttp://en.wikipedia.org/wiki/Ionospherehttp://en.wikipedia.org/wiki/Electromagnetic_interferencehttp://en.wikipedia.org/wiki/International_Telecommunications_Unionhttp://en.wikipedia.org/wiki/International_Telecommunications_Unionhttp://en.wikipedia.org/wiki/Radio_spectrumhttp://en.wikipedia.org/wiki/Radio_bandhttp://en.wikipedia.org/wiki/Reflection_(physics)http://en.wikipedia.org/wiki/Refractionhttp://en.wikipedia.org/wiki/Polarization_(waves)http://en.wikipedia.org/wiki/Diffractionhttp://en.wikipedia.org/wiki/Absorption_(electromagnetic_radiation)http://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Wavelengthshttp://en.wikipedia.org/wiki/Electromagnetic_spectrumhttp://en.wikipedia.org/wiki/Electromagnetic_spectrumhttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Frequencieshttp://en.wikipedia.org/wiki/GHzhttp://en.wikipedia.org/wiki/KHzhttp://en.wikipedia.org/wiki/Speed_of_lighthttp://en.wikipedia.org/wiki/Lightninghttp://en.wikipedia.org/wiki/Radio_astronomyhttp://en.wikipedia.org/wiki/Radio_communicationhttp://en.wikipedia.org/wiki/Broadcastinghttp://en.wikipedia.org/wiki/Radarhttp://en.wikipedia.org/wiki/Communications_satellitehttp://en.wikipedia.org/wiki/Ionospherehttp://en.wikipedia.org/wiki/Electromagnetic_interferencehttp://en.wikipedia.org/wiki/International_Telecommunications_Unionhttp://en.wikipedia.org/wiki/International_Telecommunications_Unionhttp://en.wikipedia.org/wiki/Radio_spectrumhttp://en.wikipedia.org/wiki/Radio_bandhttp://en.wikipedia.org/wiki/Reflection_(physics)http://en.wikipedia.org/wiki/Refractionhttp://en.wikipedia.org/wiki/Polarization_(waves)http://en.wikipedia.org/wiki/Diffractionhttp://en.wikipedia.org/wiki/Absorption_(electromagnetic_radiation)


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o! these pheno"ena in the %arths at"osphere, "ain# certain radio /ands "ore use!ul !or

speci!ic purposes than others$

6n order to recei*e radio si#nals, !or instance !ro" A&I'&radio stations, a radio antenna

"ust /e used$ Hoe*er, since the antenna ill pic up thousands o! radio si#nals at one ti"e, a

radio tuneris necessary to tune in a particular si#nal$ his is typically done *ia a resonator$ he

resonator is con!i#ured to resonate at a particular !reuency, alloin# the tuner to a"pli!y sine

a*es at that radio !reuency and eli"inate other sine a*es$ Alays, either the inductor or the

capacitor o! the resonator is adBusta/le, alloin# the user to chan#e the !reuency at hich it

resonates$

@adio !reuency (@') ener#y has /een used in "edical treat"ents !or o*er 75 years

#enerally !or "ini"ally nosy sur#eries and coa#ulation, includin# the treat"ent o! sleep apnea$

&a#netic resonance i"a#in# (&@6) uses radio !reuency a*es to #enerate i"a#es o! the

internal hu"an /ody$

%-tre"ely lo !reuency @' ith electric !ield le*els in the lo >I" ran#e are non

to induce sensiti*e currents ithin hu"an /ody that create an annoyin# tin#lin# sensation$ hese

currents ill typically !lo to #round throu#h a contact sur!ace such as the !eet, or arc to #round

here the /ody is ell insulated$

As early in 120s, &alaysia entertain"ent industry holly depends in @adio$ hose

cannot #o to /ars and other social area, listen to son#s !ro" radio$ 6t is such a pleasant and

enBoya/le listenin# to radio those day "y "other and #rand"other told "e once$ :oadays, e

still listen to radio$ Jouths they lie to listen son#s usin# headset$ his acti*ity need to a*oid !or

certain reason$ 9e are /rin#in# an electro"a#netic a*es inside our ears hich "ay ha*e a lot

o! "edical co"plication later as e #ro older$ his e need to a*oid$

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http://en.wikipedia.org/wiki/Amplitude_Modulationhttp://en.wikipedia.org/wiki/Frequency_Modulationhttp://en.wikipedia.org/wiki/Radio_antennahttp://en.wikipedia.org/wiki/Radio_tunerhttp://en.wikipedia.org/wiki/Resonatorhttp://en.wikipedia.org/wiki/Coagulationhttp://en.wikipedia.org/wiki/Sleep_apneahttp://en.wikipedia.org/wiki/MRIhttp://en.wikipedia.org/wiki/Amplitude_Modulationhttp://en.wikipedia.org/wiki/Frequency_Modulationhttp://en.wikipedia.org/wiki/Radio_antennahttp://en.wikipedia.org/wiki/Radio_tunerhttp://en.wikipedia.org/wiki/Resonatorhttp://en.wikipedia.org/wiki/Coagulationhttp://en.wikipedia.org/wiki/Sleep_apneahttp://en.wikipedia.org/wiki/MRI


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Diagram 5

&onclusion

:o, technolo#y has de*eloped tre"endously$ 9e can see the application o!

electro"a#netic a*es in our daily li!e$ 9e cant escape !ro" it$ 9e need to a lot o! aareness

on the i"plication o! electro"a#netic a*es such as #a""a rays, in!ra red, ;


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Reference

1$ e-t /oo 'or" 5 Ghysics E Chapter 1 9a*es

2$ e-t /oo 'or" 5 cience E Chapter 8 %lectronics and 6n!or"ation and Co""unication

(6C).$ @e!erence &e"ory &astery throu#h >isual &aps K Dia#ra" Ghysics and cience G&

4$ ?ranley, 'ranlyn &ans!oeld$ he %lectro"a#netic pectru" E Ley to the =ni*erse$

6llustrated /y eonard D$Dan$:e JorE Croell,17

5$ %lectro"a#netic pectru"I:AAE :ational Aeronautics and pace Ad"inistration(e/site) httpEIIi"a#ine$#sc!$nasa$#o*IdocsIscienceIno11Ie"spectru"$ht"l

$ httpEII$eho$co"Iin!oM84817Mtypes

electromagnetic waves h

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