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Physics Experiment Report

Experiment 6

Properties of Microwave

Department :

Group : 25Student ID : B045042!

"ame :

Group #em$er :

%eacher &ssistant :

Pro'essor :

Experiment Date : 05(05()0

PurposeExplore further properties of electromagnetic waves

IntroductionMicrowaves is a kind of electromagnetic wave whose wavelengthare about 0.1-30 cm much bigger than visible light thus it is moreconvenient to observe a number of electromagnetic phenomenausing microwaves. Microwaves are often used in our life forexample microwave communication microwave grill simulcast of!" etc.

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a

b

#

$

1.

Properties of microwaves as a wave:a. %tationar& wave' (f we have onl& one re)ective surface under the

appropriate circumstances of distance the incident wave that isperpendicular to the surface will superimpose with the wavere)ected out that surface creating stationar& wave. !he nodesare clearl& visible and the distance between two ad*acent nodes

is half of the wavelength.b. Polari+ation' Electromagnetic wave consists of the vibration of

electric and magnetic ,elds. (f an electric ,eld is oscillating on+0 plane then we cannot use a detector that onl& can detectwave that oscillates on &0 plane see ,gure/. !he detector mustbe rotated 0oaround x-axis so the wave can be detected.Electromagnetic wave bounces o metal surface becauseelectromagnetic ,eld induces the repetitive accelerated motionof free electrons in metal and it generates electromagneticwave. 2e use ert+ grate because it is made of metal and haveslits width much smaller than the wavelength of microwave.(f the electric ,eld of electromagnetic wave is parallel to the x-axis the motion of free electron induced b& the electromagnetic,eld mentioned is not signi,cant b44a/

2.Refractivity of prism5 beam of light changes its direction when passing through a prism.Ever& incident angle has its corresponding emergence angle. has aminimum that ,ts in the following e6uation n and n7 are therefractivit& of air and prism respectivel&/'

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n'

n=

sin1

2(+min)

sin1

2

1=

2

3. Total reection and transmission1. (f we look at a beam of light emitted from an opticall& denser

medium n7 4 n/ in an opticall& thinner medium n/ we ma& notbe able to see it because electromagnetic wave ma& not alwa&sget from opticall& denser medium into opticall& thinner medium.(f the incident angle is greater than the critical angle C/ then wehave total re)ection.

8. (n a circumstance where dis not much larger than *there willstill be fair amount of light that gets through the medium andreach the e&es of observer.

Equipments

ert+9eceivMicrowave

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+ Microwave generator ' Produce a polarization of single frequency microwave2+ 9eceiver ' For the detection diodide device)+ (sosceles prism made of Fraxinus ' !o illustrate dispersionand the

use of the angle of minimum deviationprovides a good wa& to

measure the index of refractionof a material.4+ Protractor 'A measuring instrument, typically made of transparent plastic or

glass, for measuring angles5+ ert+ grate : !hin metallic re)ector ' 5ct as fre6uenc& block

Procedure. !easure t"e wavelen#t" of microwave usin# stationary

waves:

Protract(sosceles prism made of!hin metallic

http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/dispersion.html#c1http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/prism.html#c2http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/refr.html#c2http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/prism.html#c2http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/refr.html#c2http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/dispersion.html#c1

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Plug in power;< =

time.

%et theinstrumentsaccording toprinciple 1.

move there)ector backand forth until

the receiver getsmax or min/

signal.

!ove t"ereector $ac%and fort" until

you #et 2ndma& 'or min(.

Ta%e note of $ot"of t"e distance

from reector to#enerator 'l1and

l2(. measurewavelen#t" 'l1 )

l2* / 2).

%et instrumentsup according to

principle 8.9otate the hornfrom 0oto 0o.

2e should getV>/-V0/cos8>.Plot the si+e ofsignal againstthe > graph.

%et theinstrument like inprocedure 1 but

with an extra3ert+ grate in

the middle.

Rotate t"e+ert, #ratew"en t"e

received si#nalis at minimum.Plot si#nal vs -

#rap"

Repeat wit"out+er,t #rate.

"en t"e si#nalat ma&/ put t"e#rate $ac% on.

Rotate t"e #ratea#ain.

0. $servation of Polari,ation:

. etermine t"e reectivity of prism usin# t"e minimumdeviation an#le:

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Place prism asshown to make AB- AC. 9otate thereceiver around ?

until the signalreached max

?heck if @1-@8. (fnot turn generator

a small anglearound A to

change @1/ andrepeat until it is.

!easure -/su$stitute it into

t"e equationmentioned a$oveto determine n4

'assume nair*1(

E&perimental ata

(. Bse a stationar& wave to measure the wavelength of a microwave 'a/ 9e)ector plate moves back and forth to make a maximum value

detector signal record the re)ected plate to the generatordistance l1 C0 cm

b/ 9e)ector plate moves back and forth to make a maximum valuedetector signal record again the re)ector plate to the generatordistance l8 D cm

c/ Microwave wavelength 8l1-l8 3.8 cm

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((.

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incidence 1. !hen rotate the angle from the detector up to wehave the maximum signal record the angle of refraction

89epeat the procedure up to we get the same incidence andrefraction angle 5bout 30 to 3G degrees/ 1 8 3 3D0. !he angle of the prim FG0

Measured minimum deviation angle min 8 - / 8H !herefractive index of the prim n7 sinJ + min/K8L'sinJ /2 1.00

(". !he phenomenon of total re)ection and transmission Ae sure thatthe receiver is receiving the signal of the max angle/

;raw with the computer the transmission signal-distanceNdiagram from the advanced experiment and answer the 6uestion

5i#ure of ata

;istance-!ransmitted signal

Error nalysis !here ma& be an error in reading the scale !he output of the microwave generator ma& be unstable thus

;istanced 0 0.G 1 1.G 8 8.8 8.F 8.D 8.C 3 3.8 3.F 3.D 3.C F F.G G cm/

!ransmitte

signal 1C8 1G 118 C1 F8 30 8C 8D G3 G3 D0 D3 DF G G3 G8 G1 5/

9eflected

signal 8 C 1D 1HG 880 88 83 8G8 88H 88H 883 1 1CF 1H HG 1H8 1H1 5/

!ransmitte

signalO

9eflected

signal

1CF 8GH 8C1 8GD 8D8 8G 8DH 8HC 8C0 8C0 8C3 8D8 8FC 83C 88C 88F 888 5/

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ma& cause error in measurement 2hen rotating the ert+ grate the angle might not be precise

thus causing error in measurement !he angle of the generator and receiver in respect to the prism/

ma& not be the same thus causing error in measurement

2e can reduce the error b& carefull& reading the scale and beforewe read the angle of the hert+ grate we can make a mark ,rst so itwill be more precise

6uestions1. escri$e t"e distri$ution of data points from

7transmission si#nal)distance #rap"8/ and also e&ploret"e reason.,ith the in'ormation I ac-uire 'rom this a piece o' ana.ysis* /e can say that the

more separation o' d is* the receier /i.. 1ot .ess si1na.+ or our situation* 'rom 0

to 2 cm* it tru.y diminish the si1n that is 1otten* and 'rom 2 to 5 cm the dec.ine

pattern turn out to $e moderate+ 3ie/ise in the dia1ram /e can see that there are

.itt.e ups and do/ns* /ith this /e can say that /hen /e /ere doin1 the

inesti1ation /e tru.y cant hae the demands aptitude to do this experiment*

/hich at .ast /i.. mae .apses to our outcomes 'rom the ana.ysis

2. 9ood conductor surface can smoot" t"e entire microwave7reection8. "at is t"e meanin# of t"is in p"ysics5t the point when the conductor creates a wave theelectromagnetic ,eld of the free electrons of the conductor meetsexpectations and produces another wave. 5t the point when thesurface of the conductor is smooth the re)ected waves can beconcentrated dissemination does not happen and retain a

percentage of the shock brought about b& the electrondischarges of the electromagnetic waves. %imilarl& re)ected andincident wave energ& is not expended so the conductor cantotall& have a re)ection of the microwave.

3. In t"e procedure 0.2./ t"eoretically V'-(*;sin2-cos2-'w"en t"ere is a wea% si#nal(/ $ut in t"e e&periment wecan sin > V>/ V.

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>. an you e&plain t"e use of microwave in t"e recent years%ome of the widel& known of the usage of microwave in therecent &ears are point-to-point telecommunications radarheating and power applications and spectroscop&.

a. Point)to)point telecommunicationsMicrowave technolog& is widel& utili+ed for point-to-pointtelecommunications i.e. non-telecast emplo&ments/. Microwavesare particularl& suitable for this utili+ation since the& are moreeectivel& centered into smaller shafts than radio wavespermitting recurrence reuse their relativel& higher fre6uenciespermit wide transmission capacit& and high informationtransmission rates and receiving wire si+es are littler than atlower fre6uencies in light of the fact that reception apparatussi+e is conversel& corresponding to transmitted recurrence.Microwaves are utili+ed as a part of shuttle correspondence anda great part of the worldQs data television and phonecorrespondences are transmitted long separations b& microwavesbetween ground stations and interchanges satellites.$. Radar9adar uses microwave radiation to distinguish the range speedand other 6ualities of remote items. (mprovement of radar was6uickened amid 22(( because of its awesome militar& utilit&.Presentl& radar is broadl& utili+ed for applications for exampleairport regulation weather forecasting ships navigation andspeed limit re6uirement. Microwaves canQt be conve&ed with

usable pro,cienc& in customar& transmission lines &et re6uirewaveguide such as a metal funnel. 5 Runn diode oscillator andwaveguide are utili+ed as a movement indicator for automaticdoor openers.c. "eatin# and power applications5 microwave oven passes non-ioni+ing/ microwave radiation at

a recurrence almost 8.FG R+ 18 cm/ through nourishmentbringing about dielectric warming principall& b& retention of thevitalit& in water. Microwave ovens got to be basic kitchenapparatuses in 2estern nations in the late 1H0s after theimprovement of less lavish cavit& magnetrons. 2ater in the )uid

state has numerous atomic associations that grow the ingestiontop. (n the vapor stage secluded water particles retain at around88 R+ *ust about ten times the recurrence of the microwaveoven. Microwave heating is utili+ed as a part of modernprocedures for dr&ing and curing items. =umerous semiconductorpreparing s&stems utili+ation microwaves to create plasma forsuch purposes as reactive ions etching and plasma-enhanced chemical vapor deposition PE?";/. Microwavefre6uencies regularl& ranging from 110 S 1F0 R+ are utili+ed asa part of stellarators and all the more outstandingl& in tokamak

experimental fusion reactors to help heat the fuel into a plasmastate. !he upcoming (!E9 thermonuclear reactor is re6uired to

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range from 110S1H0 R+ and will utili+e electron c&clotronresonance heating E?9/. Microwaves can be utili+ed totransmit control over long separations and post-2orld 2ar ((exploration was done to anal&+e potential outcomes. =5%5worked in the 1H0s and mid-1C0s to research the conceivable

outcomes of utili+ing solar power satellite %P%/ frameworks withexpansive sun powered clusters that would shaft shut down tothe 2orldQs surface through microwaves.Tess-than-lethalweaponr& exists that uses millimeter waves to warmth a meagerla&er of human skin to a terrible temperature to make thefocused on individual move awa&. 5 two-second burst of the GR+ centered bar warms the skin to a temperature of GF U? 18UI/ at a profundit& of 0.F millimeters 1VDF in/. !he Bnited %tatesIl&ing corps and Marines are presentl& utili+ing this sort ofd&namic dissent framework in altered establishment.d. ?pectroscopyMicrowave radiation is utili+ed as a part of electron paramagneticresonance EP9 or E%9/ spectroscop& regularl& in the $-bandregion W R+/ in con*unction ordinaril& with magnetic ,elds of0.3 !. !his techni6ue gives data on unpaired electrons inchemical s&stems for example free radicals or transitional metalions for example ?u((/. Microwave radiation is likewise used toperform rotational spectroscop& and can be consolidated withelectrochemistr& as in microwave improved electrochemistr&.

ppendi&Microwave radiation has lower fre6uencies and longer wavelengthsthan visible light. Microwaves with certain wavelengths areabsorbed b& water molecules and can be used for cooking. 2ater inthe food absorbs the microwave radiation which causes the waterto heat up and cook the food. !he water in living cells can alsoabsorb microwave radiation. 5s a result the& can be killed ordamaged b& the heat released.

Microwave radiation can also be used to transmit signals such asmobile phone calls. Microwave transmitters and receivers on

buildings and masts communicate with the mobile telephones intheir range. ?ertain microwave radiation wavelengths pass throughthe EarthQs atmosphere and can be used to transmit information toand from satellites in orbit.

Reference1."ationa. %ai/an niersity Genera. Physics 3a$oratory #anua. 205

8. http'KKwww.bbc.co.ukKschoolsKgcsebitesi+eKscienceKa6aXpreX8011KradiationKtheXelectromagneticXspectrumrevG.shtml

Review%his experiment needs coordination $et/een partners to $e a$.e to 'inish the

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experiment 'aster+ rom this experiment I .earn ho/ to 'ind theoretical formulafor the three curves of observation of polari+ation