O-Level Physics Complete Revision Notes MAGNETISM, Lecture notes of Physics

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‘lta | 4 | ~ | Au} | i +. HA roe a pan of magnetism: is motion. of eleittons Vc eg Kron of electrons anes ase tolmagnst ic field| ||: iseouien it) JOLIE “|in a. permanent magned , all the! ‘ajoms are magne! “atons., and! they ave_aligned in. 3 patdetn 564 ina _bne'liend is_[nss th) pole and ihe! owner ia — south pole. | LI a =|[n\ a magnetic material, alas). alll the. lems are| magnetic oioms), but they are _atran| din aul Jdishrdered ander iknu's sd here is! sain poe Of ‘south fa { | === } rel me “tn. non. SiR AIN fe! pares ‘ailadoms are cote cE | ees oh Jes (imbmesn aigaet Ce) el LI | oe 5 = HARD MAGNENC MaLERIRI | ai =Magaeticmalteral which are hard 70 ighene Jf pieoins nei2e 6 requires artery magnetic, held to | gndtse but refain thor. nS 4ism_Ylonger|. peta their! ingen ven pare magnet 1 fel = ea | + | Tse jo)Ner good fox making). pes mané & bar rengries S> Bens | di ft | + = Sce D [ORS U) =a ee a, SORT ee ATERIA cee otal maternal. whichiave|eashiy\: m d¢ tan fe mag ni tised = | EF fia 4 i netsed | steel ban, vutwards with! 4he |uniiie lok Fa peimaneint, mage at the same, Lime This! pee i “more “er ficient dnansSingle touch metho \ | |*'1n\ both dhe methods , fl nels must ibe lifted iy ab labove! the! steel bar: ak the? end_oF each) sho kel “The pole. produced at ne end lok; the magneticed steel ibar! ch et Case, sioking is done, from| the |center elas ‘a ” " | polel. PELCCIR CAL OETA : Dic yp Aly The ‘steel specimen to be _magnetised 1s placed ina faced! inside S| L Lcardboard cylinder. The card bvard! is_p | solenad!. A “solencid, has_ Several hundred) durns_ pe | @oppen wire. | ¢| When 3 divect curfent is passes through the: solenaia 54 [becomes a magnet Butchi on the curvent! ‘for 3 wealth The pam@onotised steel specimen is found | ieee when removed fom the Solenoid the | polarit pre | iva | F@n be determined by. right hand ane | Latter Srey IS of opposite elon fo ial ai fie mdael T y i | Current Ypward | Current: gownwar | es aaa freld anticlockunse maar Field Locks | dorreni out of : convent on 0! the page. magnetic fel (aloe fodgreh id Clos i Tol Gorkwiteldicertior int { =e (Cea BLeechn eye => NokT __|Whenl_aimaqnet_is heated strongly with the means of the |_| bonsen_| burner | Hame!, ine magne? will lose! its ren due | ltoline incveased, wbrations| of the atoms. oF the mans puinich | Cayse|_tiny magnetic atoms! fol lose. Their es Thys ne a von. is Hee Sy indi L iE troactt +} ai i {\fa)so1| me magnate aloms. to Nose. their aigamanh, | secs se | magnet Lose! AS mee mer! od alten ae i elt lis! the most tne metinod of dena galisd id. {ni _ this method shel magnet iis (placed inside a golenold sal tonnected tb ‘an RARE tut tent supplg. The magnets then slowly | removed throu! qn} tne suehoid Onin He | | alternahing current 1§ Flodin lie! | si ae ae Fes about 600. oo ame 8 labbud 2-3m long. | | Scanned with {3 CamScanner’: | =o z | Ee oh ping en Brass Seu esa Aste endian al aaa) Ae on e\ ensured that there (s_no: oa agnetic | 7 FA | | a oth other th than! tho carths Pei Feld’ araun) — f et | af ¢ feegl camps |: | [STE Ns a { ! A | y }—-;—_L_}] = Ee aia | (eat + c al L | dt al sles aroun Experiment to ph na lic, field es Be u riet eee ee Chi 7 po ee eee ! alee EeomGan ‘Simagnetic. ‘north FAC ES re ith Ge then = = caeaenats iS the g¢ po graphical sou fhulandlvicell a ie ogy aa) ae ; Coco) ieee gate ta [s imagnebiclsauen - Ls, lating compass a a al white paper = at ir ene bar magnet is placed at the centre of 4a White, pfece of paper, so that its end pole (N pole) Faces geegrenial ach and _S poe faces eogvaphical south. © plotting compags is_placd| near 40 the endeole of, the bat_magn +. The position. of the pointer. of the! compass i's marked ‘witha dot-The pletting & en moved and placed! on the dot .The new position of the pointer lis marked with @ becond dot. © The process of Aan Lee dots is repeated until Mie compass) feaches the ole of the bar magnet. ©The dots are the fond to get the maQnetic Field pattern &- the digection oF 4he pointer of compass indicates divection of magnent Filemntflmel tei htetmer tit Oca ——— = | i} experiment +0 show magnetie Ce ronda current | 7 (USES or CLeeTrOMAGNET A) pene t mento ae + Carrbng- | conduc ! ae Gere Senet ip abletinic belle heosrat fA omen! | [eal if 1 nny ase) | Raabe [= & thy swikch Be rin | cai i rt ae | | : nae |e switch supply aq | cardboard with hole io rai 7 wi oe 5 |_y stiff wite iT ical eal meer et ® a OThe tircvit is set up as Shown in the diagram above, Some icons Filings ave sprinkled on AWe cardboard when te ewitth is Soe || | electrornnagraly eet | closed, The Filings are aligned in a circular. pattern! around [the (ji 4 || F-gorg St | wite showing the presen oF the magnetic field . —— | am Y 6) |hammer, | Wah’ the nieostat , ane evrient in the ciccut (increased 2 |. | \ }| 11] 7a itis Found that tra tron Fillings spread ove v2 larger region = } a: Forming. larger radivs Of orcuiar pattern, which shows. that Ue Meet pot, - = 'wWhen the bell circuit switch| 1s closed, the lcrrcvik vs completed magnetic Feld 1s sare when current increases . G jron tilings are remove % dhe plotting compass is. placed on |) _lBicurrent! Flows throvgn the electromagnet | | the cardbdard.A dot (§ marked at position of the pointer: of tne += /u\The electromagnet becomes magnetised “iB theret Compass. The compass is placed on the dot & the rew position of the +‘ _|soft iron _armature|.This enables. the Hammey: to. sfri pointer is_noys marked . L ja) As soon as the hammer moves , the (ircuith iis broken aint athe experimen! 1s cepeated until a complete circle is formed. ~~" |point of ntact .The current ‘slaps flowing #electroma @ The direchon of curvent inthe circuit is reversed & yi back +he armahe » femakin g the |contad) IS } The direction of the pointer is the direction of hy meena field.! | _|leseo_ iS magnetism. This allows! the. 2p ad : = adie ith a difection af compass reading is observed completing the Uv cuit! again. ona = wt larger current , he magnot: ic Fleld strength increase fa We iat ora aac ama a) (J mare as_the Cirquik switch Is : {sea a) 2 ih arcend the wire’ sai ss - ZT} ~ le vyoward Airech inn of current, magnel/freld if Wis a type of magnet in| whechithe pay ileal Al anf cfochwise Ca doanwanl direction , the magrehic = proguce? by an electric curren IP consists | of, wires ewdume fidd ts Clackusse , —* [afte a corls When current | passes thraugh the! collar madaeli field is produced. When curvrent suppl ee ‘e 5 zu arpundl a fron. no gained coil is vsvally wind agne id a_magnete ferial (Soft cs) © current caccying! con rela aroun conductor Pp aHecn, but alterna Sield thal. reverses dicection peris ip. Direct current Flowing coduces a magnetic field! of 2 es Apa peo Cl BPA PS ak du cor. prod atross Q I certain = Fee a) magne tic I CULteNk pt really ° i ting E Ma. a retains magnetism long time. : 2D ditfitult tomagnetise 3) difficuit 40 demaqnotise 4) weak magnets 8) made of steel R 3). easily 6) relay, electric bell | & pL molor, tovd speaker Magnetic shields aa aaa ~~ talwhen throu: nce, (ther yaqualtie i M Corrent_Flays_thravg h_a_wice, ‘there ts magneticfie NBs © | Ty magnetic shield equipment 4o| be protected iB oces 3 magnetic ine Lemioarary magnet a qolretan (magnéhtm’ Cor ong - easily magnetised -- i demagnetiSed » Ih 9) Strong magnets _ : aS 5) made OF Sof+ iron my -“@lemings [ett hand motor we? || Jirefager > magne Fld. ene 20° by pl Fg 5 Corian cariylingy conductoy, 1 faced ina magnet field. | 1 as a 1 — {Ea elale iy] Os a See — $ arovot tt. /G!When a curcent carrying wite 16 [placed ia ‘Majnelic Field, tere Sa resultant force varising becavse oF i | 2 magnatic | fields. J imac | | | © The Condvetar moves in Au _difechion, of HMeltesuitant force | | tiem aes Second “finger >~ curren 40.Ve) pum Thumb ae /motion(F) | | | —L Neld vpeuerent =90; 20 | (ehngey =4 eT] *Force20_, no movement | | A Direction oF cusent 2 magnetic freld. is. given. ¥ Direction of force /mation has_to be. determined: 9 When current % fie ave pavallel_or anti =parallel the fore0 Thus no_motion.. A Fone only acts when current 2 magnetic: field ave | perpendicular. =) It shel dice ctran|_oF cectangular | wire 1S reversed! 7. chou hice x Keeping bw | direction oF magnetic’ field am, then deci ala. | ob than wil al @! |t the direction of corrent remains) uadiant ied DUE thal of magnetic field 5 reversed), then thedire tion af fotatign 4 |. et che rectangular wire is reversed. Oca Easaras (ase 12 Into the plane/ovt of the plane CO CH fale + Q: Out and into the pl © © tiny is there a_forat acting? @ LYK IR. Interaction of magnetic Helds by~ permanent mag ners. e 9 Je-tutlen ton the condv ctor. etbett lof Soft iron core L a Vcoet tran. core > Strength INU ASES + magnitvdle of 7 ind_belween 4Wo current carry © Length of wires 6 80mz. © same current pay ny vhrough To. Wit . Parce 15 algo am ¢ dipechin of force towords each other whon direckion of eurrent Xe FOMA. © thy’ tha wives Move towards Cash other. oe. © ength af Q wits if some. ° ae idvdo gh coven! puasiog through the wired-- © Sedo oP curionk ts opoyite fa QR wiry. 2 prageitwl2, ob farce 2 sai, + direction of farce v& cwayf from eaoh thar o GS. Pho wiles ropa rach othar . Scanned with ce) CamScanner’ a a oe ee be The magnitude. oP cuntent in He tircut fe ircrorvert hte Lxperimant_|+o ceri tho. cprrent carryird, conductor defection Of tro uste loop s&s observed z Jina magnate field = when tno a current de through WG wire from Bioc the wire moves outward. Sa wa Whee tha) direction of cusrcent ie eyerse, Ioaping i direction oF magnetic Pield game, Hie wive | roves | inward). | ve Won direction of magnatic poiacii Lig veveysed. ‘Kappiing ” rhe aea direction | same, to Ly) | moves inward. 4¥41_wWhen the current inthe wire. increases|, Ihe} angle of L deflection _also_increases » showing ttl ppaee force acis on the wire - _ FB when Fhe direction of current & magnadic patty, toth_| | are reversed, the wire moves ovtwatds., induction +s () (0) () 0 Magnet Field vines. “=> Magnetic aye y g | © Continvots cutting of magnetic! field lines gg! | Wire loop horses hoe permanant magna 1A stike, -wite_in \ fecongviar_ snape (N8¢0) f a. Stron permanent — howseshoe. magno! 9) Gol D-C: supply - (2) | 441 Ciceuit with |ameeder_choostad Rate of change oF mmogratic <—{8 Flux. linkage Te rectangular stift sie & placed belaeen rho 2 opposite poe of 46 fhe| permanent magne} , 40. that a an suing freely. Q3 Shown in patil dagram.. 1 Gis the rectangular “wires connected Pi a complete circuit, | consisting of a OC syppy , ommeter, rAoos/ al: 2 suiceh _ >? Faradut's law of induction susan AR Ca corrent iy \switchok on 8 tha direction im which de unie move iia obteived To dureshin of: convent fs raved, by tag He mognalic Hi states! thak tho induced emt enerated in a_condudr is rparatons tp tho vate of ae of rmognsei A flux linking) cha. cidit | | | | | olarily game, Now ta divectian in which | fa ie. is. observed. bo io | me eee era, & ini jing direc &bn Kea i trent Same... | va n0- of fi ns.in the coil fhe_direchin (6 Qutith. the. lade 5 oPNVOd — AN df “ty ets direction | of magnet} field. Bev oot mic cilete gl dhe dwechin in which unve_mover n\ observed. Scanned with ac} CamScanner’: Tae ee ne eee ee air S r Fat ial an ment ar. | {ea i j i open, Eha_compass needle gives.mo ry Pas iia Opposite di iad we Bee « ane | sas Yea) era wah il: Nol vel dons ele ae Sey netic flux oC {throug iatnt B TAURI | are | Ngo 2 in opposite direction, causing. an. in ced curcen in® ‘oN - ae at ae me e os z the reversed dicection., nea "5 is. kepk open, there is no mages through the cil B detection |S) zerd.. FRansroRMe R Tisns Gabe = Ss “ | Loy a ee earie| Ptaminated sof iron} Co ess % Ve> Vo" "es ah [pala a or lid ei Ielotstochel abel : fre cae t pole I Power input = Power output | 4 4 WV eal St ae load) | !P primary = Paeemdary IL 4 aK) [a] \pVo1 =| Isve - Ip Fisecendary | aia [ tIpl_= Vs 4 primary’ I (a \s\| Ve Ee coil - Np = no.oF durns!_in prime cot! a no. oF /tuins_in Second ry oil lp > primary | input yauset Y =, Secondary jrausut voltage oc a BEE Lene [|S Bl | | ia | e oN] | {oe f : The_ principal lof! operation oF closed| corel transformer! be {This irons former: is bayed| anu Farad byl’sIiron rin lexperim ia | = | | | = current % etimary Corl if = concent in| Staind coil Ltt Tionsformes dransfers_ electrical energy Evpp. jedi fone tine : IC | = primary Coil, to, the | sx condary} coil a ager na i einductia StruCture of a closed! cove |Yronsfoumer.: The trans former| | Ie! [al _lpetwetn He two oils. sla consists | OF two cailS OF wife) cne called primar | the other Sl mht the primary toil, the applied alienating! val Gelseisiy a called secondary. Goth |2Mo_ coils have appropriate aumnber,_ Gu Vg changin magni tie. Field’ which induces ahh et is dvins. An_AC supply is connected f0_a pramayy coil The tw coils = Sean d Ory. cuit. ah are wound on a. Idminated svét_iton corel, which consists oF! | a i le Grep-vp- (transformer 1s one where tna! em4! iq 1_theal ercondl r thin sheets, oF SoFt iron ,1S0\dted From, each other by a.coating = = ay} chill 1S greater Man the emF! in the pana CHE of last The (amination of the ‘soft iton core reduces. the = le5¥ép. down transtormet, is one where the eme altho hent 108s due 10 tnduced crrents in Ane coal). Stet = cause secon Kea Oll_(S (ess nan the emf in tim ima lige ot = ; |e ae {_} Ee | ca cable Se lowcurcent bron Maio = - ita = =i sured] hyp voltage vd Hae = Tnput |_| output inp clu mout retin ma vs > Ve Is >Ip Is 2\p Vs>Vpi | hese Pout = Power Delivered 0) cable by step-up Aransformer_| T= Cunent in. cable (ow) il el ea Wf BA i V = Voltage in cable (high) 5 Pearce eis IC power. loss in. cal whore R= bie, Rive = [2 Ro resistance of \able | 4 .C. Generator gy bon push) || Ae = Slip) rig) commuya tor “etal (ene PKR IE i. T Piss ae |S pres ons | EES | SS OPeRAON oF LoupSpenkeR | || = 4 so 5: noe ATS mm = A_oil is wounded! around_a. cyindriel jube & kis | | Lae connecte cl 40 on AC supply’. paper cone is attached! to ‘ho tobe. When_tho Supply switched: is closed, direction| of cuvrent! _—~ |= eeverses in| Me coil Ko 'tho direction of magactic polavity! ix Me.” coil also severses.The Ni pok of the permanent magnet =|} aitermately repels % attracts the cone (Hovey & this the! one maves batkword 1. forward . AS the ane moves 10.2 |fro., Leas onsequbve compressions & rarehracvon dye _prodyted in Ae pasts, ths longitudinal wave #8 generated | | al ja liege cs) ACimgenaravar: ( DC motor, 14 has a DC svpply in. the external tircutt- The direction at tna curvvent in the coil eeverses in every Male rotation . Uses Fleming LHR Current carcying call és paced in the magnetic eld, $0) thore (S _ ats thecal, ‘applies hy the muppet field 2 Coll moves. in thé:direction of: Coxe |_| Has_ splitting commutato? Pur aft Split rit 15.40 rGerse she drechion as iearctren in Ihe (oop ) whonever the commubalt changes contact! Arom_ane| brvsh 0 te oFhoy There ié.n0 povier poly inde S external ctecul \ The direction oF the curtent in j Yne external |eircuit reverses in. evety half | cotation. ile -VsesElemings RXR) | | § Ag ihe cal rotates in the! | > maqgnatic field, it cuts. thro’ them@gnatic Feld line, a flux linkage, otcurs which indyces EME % curcmt in teal Has slip ring, comm vtatot = {6 purpose of the Sip. cing is to_onsure| that theidiyectign | of tna Induted wwr(ent in tha) external cirevik changes with_* half rotation OF the cain! extemal _ O¥cvit:!|_19.4) Herabing | otkar words, Sa a {in| Hep!) etltt wi $ ment a 14 tive patenbial j == | Sima Way aa me iaaeeg en ase ~ =] iy flvavestenty ly iu sa i\-seréen voltage) xolates Be! aa very) lea aan atl ried faked ositive potential! — cr rl High voltage” PR aI —— — | Election Gua | [Straporents | = electron. gun a > detecting plates | aaa = Flvorescen Screen’) =a] Elecdcon Gun aha i || ==" Lt eonsists oF] Filament. grid 8 accelerator. Electrons ore liv | | emified |from. ine. heated filament through p.pcace $ éalted Aneumiane emission. [grid is connected ‘to a negative polenta: The mote “neg [this !p == gt enbal,| the mores dectrons! will be. repelled! 10 a Igrid | etl fewer | etectto ns! will ceach thee and tine, screen (d iterates “ak mit Green sethe’s the number! of electrons reaching ta fa —| brightness fof! the Light! Hence % the! no qative (potenti “i ~ qud—can-be- ad of betgniness canis | Tal “The actetbraltor is) a) cy tindrical ancde Zi Connect fed Beir jwill be _accelecoted ati high Speed el the | miovgh the Ave potential atce reraton (Bel He The Tal high! positive. potential ai several {hoosaind volts es Mesto are fo.vsed ento O fine beam, _ ae I es CE ca ‘o Deflecti esi: qwo pairs of plates are filled m_ the CRI0 Méltages._! Fain [rime ase] Twme.lbas eal! fan be | applied 40. those! plates to deflect the blectod a MSs PAe tra 2 1 Te Tonal le beam he. Y-|plates__ cause debiection in tha vertical | dimension when a voltage. is Applied across them!On | the other and. the. 2-.pates_ Cayce the! electron |beam fol deflect ini the| horizontal. dire ctron (E/o| voltage 15 | appited across them : PE] iq id : ial | 0-5 Vii o Fluorescent screen: IEG 44 the sureen is coated with a fivorescend salt ear! |b alata example , zinc suiphéte (ZnS) . when the [electrons hit = 210} Away the screen a cause! the satt to produce aq t\ash | i Of light!_an nce a bright Spot_on|_the! _lsalagy 9 e) 11g aie On El Se { = Fle 5OHz ane the inside oF the tube is vacuum, ‘solanat_elecrons p= pe ate tov fi) Er do not \collide wiih the air atoms, get: detiectod 3 | Pe apes AS Hine ease lose energy. ll I ‘| | | | | _ ama basiaee, goin = it omni = 20162 | “0:01Aiv]_ ogee ea aaa ae Sl a! re 252, |Y¥@ain peak voll age 8V/div. F{5V_| | [time bas = O}'04 sae | = | 109 /div 1 Pal | (ie |= alla cE | | |For. fale) ima [DC [supply | we see a dot lor spoh of _|screen_|when the time pose! 15 OFk s DC_suppie_s we see a horizon tal! swnen sime | base's on. | ca