Story of Electricity (Tell Me Why #126)(Gnv64)

WHY IS AN APP NO IK HIS?

ANRAA

   KO  FO CH   t     g t

www..momolicom www momolicom//ubcib

WHY IS AN APP NO IK HIS?

ANRAA

   KO  FO CH   t     g t

www..momolicom www momolicom//ubcib



TEL ME  

h   om om::  o  FRO  OU OF  P  W YB  &    D

he aster evant It is the invisible force that runs through the veins of the modern world, making it go. t is so much a part of our lives that its presence is almost ever taken for grant ed. Electricity is a natural force that was tamed and put to use by Man, many cen turies ago. t is like a servant turned mas ter As Man's lifestyle improved, through countless inventions and innovations, the support of electricity became vital to His existence. Absence of this invisible servant would leave the present-day world powerless and dead This issue of Tel Me Why tells you the fascinating story of ths vita force that rules the moder modern n world world  Electri Electricity city

Why i i aid ha he ino ducion of elecriciy changed he coure of man kind?

here hae bee a idef iite umber of etios that hae chaged the ery course of the word, makig it the amazig place that we ow ie  But few hae had as much mpact as eectricity. To uderstad ts sigfi cace better oe should, rather, thik back to a world without electricity This will take us back to a time whe there were o equipmet like the  refrigerator, fa, mixer grider, or computer ad ee worse, a tme whe the world wet pitchblack after dusk Dot you thik this must hae bee qu te difficult?

Eectricty, therefore, has bee a pathbreakig o atio that made lfe easier ad more comfortable As years passed, more e tios faoured by eectric power were made. Hece, it goes without sayig that the chage caused by the troductio of electricity is uparaleled, ad a life wthout it, uimagiable

e need eectrcty t perate ths

Wha i mean by elecrici ?

 lecriciy i is simpes erms is a fom of eergy. I ca also be associaed wih he pesece of eecric charge. Eleciciy is usualy produced by coerig oher souces of eergies like coa aural gas oi wid soa ucear powe ec. o udersad he moe me of eecric chage oe has o fisy kow abou aoms. You migh hae head of aoms aeady. Eery mae i he Uiese icludig he hu ma body air ad waer is made up of aoms. They i ur are made of ee smaler parices. A he cee of a aom  ies a uceus ha is fomed by posiiey charged proos ad euraly chaged eu os. Negaiey chaged paices caed eecos spi aroud he ucleus. The umbe of elecros moig aroud he uceus

is equal o he umber of proos i  he ucleus The charge of a poo is equal ad opposie o he charge of a elecro. I is also o be oed ha a hese cosiues ae exemey iy  eecriciy he paice moed is he eecro which caries a charge desiga ed as egaie I ohe words he moeme ad accumulaio of egaiely charged eecros i eaio o proos ceae eec riciy

Did o know? It wa the Eglh cietit William Glbert who trodced the term  electricity He i alo cedited with beg the it to make cietific obevatio o rictioal electicity towad the ed o the 16 cetry The fidg were pblihed i hi book  De Magete 

commo charge cares ae he pos iely charged poo ad he ega ey chaged elecro A objec is egaely chaged f i has a excess of elecros. As pe he Ieraoa Sysem of

Why i eectric charge impoant?

 lecrc charge s he physical propey of ma er There ae wo ypes of elecic charges:posiie ad egaie Like chages (posiie ad posie for example) epe, ad ulke charg es (posie ad ega ie) aac The mos

6

Eectons ovng aond the Nces in deent paths. e Me 

Visaisation of Protons and Netrons at the centre and eectrons ovng arond the nces in an ato. U (SI) he u of eecic charge  couomb whch i euae o abou 4x e.  eecica egeeig he ui i ee a amperehour (Ah) ad i chemy   commo o ue he elemeay chage (e) a a ui. By coeio he chage of a elecro i   whie ha of a proo i + The uaiy of eecc charge ca be mea ued wih a elecromeer. The udy of charged pai ce ad how heir erac o ae medaed by phoo  caled uaum eecrody amic   

Why a the dicoery o pro ton impoant?



poo  he poiely chaged ubaomc paice locaed de a uceu. mpoa ae Proo becaue  i her umbe ha deeme he eleme (of whch he aom i pa) ad  chemica popee. To pu  imply he umber of proo i a aom or he aomc umbe defe he ype of a aom. Thu a oxy ge aom differ fom a heum aom o he ba of i aomc umber. Tha umber  deo ed by he lee Z. The word poo' wa deied fom a Greek wod meag fi'. It wa amed

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Who identiied the eectron?

 lecros, as we kow, ae ega

 Thomson y Ees Ruherord i  920. Oe or more proos are pese i ee y uceu s. Togehe, poos ad euros orm wha s kow as uceos. Fuher, proos are made up o isile parices caled quarks Thee s a sog ucear orce ha ids hese quaks wih each ohe.  s also he same oce ha prmaily coiues o he mass o he po o, aher ha he quarks hemseles 8

ely charged suaomc paricles They are ery i mpoa ecause o her oe  aious physical phe omea such as eecrciy, mag esm, ec The hsory o elecros daes ack o 1 838 whe Richard Lamig pu oh he cocep o a idiisile quay o eecic chage o expai he chemica propees o aoms. Yeas ae,   89 1   sh physcs Geoge Johsoe Soey amed his chage eleco . Six yeas ae ha, Brish physcis J.J. Thomso deiied he paicle The wod eeco s hough o e a comi ao o he words elecrc ad o. Isde he aom, elecros are  cosa moo, reog aoud he ucleus.

They possess a cea amout of eegy to maiai distace fom he opposiey chaged potos sde he uceus.

What i meant by elec tric current?

 al we alk abou eleccity as cuet. Bu ae he wo same? No

Charged Experiments! I i aid ta cet

Lets see why As we hae see eae, eecticty is a fom of eegy. Bu eectic cuet, o he ohe had, s the moeme of eecc chage. Lets pu i bette. I  s the fow of chaged paices though a medium such as a wie. Si mla to wate moecues moig dow a ie chaged patces moe dow a coducto gg eectic cuet. Coducto meas aythg ha alows he moemet of elecc cuet fo example, metas, ad some lqu ds Elecic cuet is measued usg a dece called a ammete. The coeioal symbo fo cue is I  The tesity of electic cuet s measued i tems of ampee, amed afe he Fech sciets AdeMae Ampee, oe of the foudes of classca electomagesm

 he pat ued elecrc charge o tudy te aure o eleccty. Oe of te ealie itrumet hat helped i geeatig electric cage wa te eleco atc geerator developed by Fraci Haukbee SORY O EECRCIY

9

What is meant by static electricity?

S tatic

means steady or unmoving I physics, static electricity refers to that eec tricity which remains steady in a charged body It is some thing that we come across in our daiy ife . An easy exampe coud be the electricity pro duced when an object like a glass rod is rubbed agaist a piece of sik. Wonder how that happes? Let's get to know The fact that eectric current is produced by the flow of elec trons is something we already know by now It is the friction between two objects that often resut in this electrontransfer This is how static charge is produced too Take the example metioed above Whe a glass rod is 10

Lightning- An exampe of Static Electricity rubbed against a piece of sik coth a few electrons from the rod moves to the cloth As a resut the sik materia turs negativey charged because of the excessive number of electros. At the same time, hav ing ost electros the rod becomes positively charged As the process of rubbig co Go away,

I have static electricity.

T M W

iues, charge accumuated o the glass od creases, ad the pool of elecros hat is formed o the oher ed creaes wha is kow as satic electrcity

Why i it aid that the ecret of tatic eectricity wa known to ancient Greek?

he Aciet Geeks tred o study i some two thousad years ago. The ma behd this atempt is kow to be Thales of Mileus. He did reseach o he piciple of saic eecticty. Aroud 585 BC Thales coduced may expermes eaed to statc eecticty, a cocept whch was o coceied l the He ubbed fu ad cohes agaist ambe to sudy more about the pheomeo. Amber s fosslized tree sap which s a pascike ocoductg mae ial. Athough he could o defy he secre foce behid t Thales was smart eough o see though atractio bewee ulikely objecs He coud o hae compeed hs study due o ack of esources ad oos. The Greek coibuio does' ed wh hs icompee sudy The ery wod eecricity' has bee deied from he Geek word elek ro' meag amber' SORY OF ELECTRICIY

Almost Evehing! Ameica iveto Thom a Alva Edio i cedited to have made moe tha 2000 ivetio cld ig almot evethig that we ow e i o hoe elated to elec tcty- witche e electicty mete etc.

haes of Mets 1

What are conductor?

You may hae heard aout

coductors aeady They are mateials that allow eectros to ow eely om oe partice to aothe. The capacty to trasmit somethg such as heat or eecticity s termed as coductty. Depedig o the coductity, sods ae cassiied as semicoductos good coductos, ad sua tos. Oects that competey aow the passage o eectricty ae caled good coductors Pue sier is perhaps the est coductor we see aroud Some iquids are good eectic coductors too.

m not a conucto

Siver ars Geealy, gases are cosd eed to e poo coductors. Ths s ecause ther atoms ae too ar apat to alow ree low o eectros Ou ody is said to e a good coductor o eectcity. That is why we ted to eceie electic shock rom applaces o elec tc equipmet. Isuatos, o the othe had, do ot permt the ow o elec trcty at a. Amog the com see suators ae glass pastic, mica etc Some materas ke germa um ad silico eog to the categoy o semicoductors. Ths meas they coduct eec to ow uder certa cod tos Otherwse they act as poo coductos ell Me 

C Hg Spee Electcty! Sciett have proved that electrcty travel at the peed o light That would e more tha 28,51,02,627 metre per ecod

What i meant by AC?

 ectic crent moves

often l ke a wate stream. The only dffeence ee is that electric charges do not always move n the same dection. When tey do it s caed Drect Crent o DC On the oter hand AC o Atenating Cent as the name sggests occs when carge car es in a condctor o semi condctor evese thei drecton of movement in a erodic manne SORY OF EECRICIY

Wth AC t is ossble to rn many tyes of electcal eiment ike geneators motors owe distib ton systems etc and aso kitcen aiances TVs electric lams etc ence for almost all hgh owe acatons t is a gobal trend to se AC nstead of DC becase of ts igher efficiency Besides tese

I Drect Current Grapcal Repreentaton advantages over DC AC owe is believed to be less exensive One can aso se high votages wit sma cents to redce losses with AC ower It was i n the 1 850s that te ate nating crent tecnoogy first s faced in Eroe One of its ionees s te Fench inventor Giame Dcenne

What  meant by the term DC or drect cuent?

 ternatng

crrent as we saw erodically everses ts drection

13

whereas drect current (DC) flows always in the same directon The amount of current can change in a DC circuit but their general d rection remains the same Perhaps the best and the simplest exampe of direct current is a battery. Take a ook at one of them in your house. You can spot two terminas ve and ve If a wire i s connected to these two terminals it wll cause a flow of electrons resuting in the pro ducton of eectricity

Aernang Curren- Grapca Repreenaon Other than this direct current is used as power supply for electronc sys tems and also for chargng batteries DC s thus used for many purposes though for smaller and less compicat ed ones unlike AC power. But direct current can be conveed to alternating current through devices lke an invert er or a motorgenerator set. Direct current is produced by vari ous sources such as solar ces

14

The Biggest Source Coal i the bgget ouce o eegy o po ducig electicity Bu ig coal i uace heat wate util it ge eate team It  the ued to dive tube to poduce electicity dynamos etc. It manly fows n good conduc tors such as wire but can aso flow through semiconductors nsula

You want dect cuent? Come wth me

os and even vacuum ecc cuen n DC s measued n ampee and volage n vos

Why i it aid that the earlier power tranmi ion ued direct cur rent?

Howeve n he couse o me aenang cuen ook ove and eecc ansmsson became ease han beoe We have seen ha hs ype o cuen can evese s decon and serve bee han DC. In  4 he s long dsance A C lne was bu n Ialy povng ha AC

Dec cuen as we know s he ow o elec c chage n us one decon he hsoy o elecc powe ecods hahe s commeca ansmsson was made possbe usng dec cuen Ths was pehaps because DC was he ony opon hen Bu as me passed  poved o be nsucen Because wh dec cuen voage couldn  be changed easy Wha made  wose was ha dffeen casses o loads o nsance ghng moos away sysems ec equed deen voages So o hs hee had o be dffeen geneaos and ccus SORY OF EECRCIY

An Eecrc Subaon was bee o long dsance ansmsson As yeas passed newe echnoo ges wee noduced By he md  950s an advanced ype o dec cuen ansmsson was deveoped and was named he hgh voage dec cuen ansmsson oday  s he alenae and he mos accepable opon o ong dsance buk ansmsson o eecc powe espe cally beween counes 

Aeano Vota

om one aom o anohe I is saly spped by a baey o geneao. One can obseve voage in he elecica appiances ha we commony se. We oen see he bighness of ligh blbs dimming. A eason o his cold be a change in vol age. So as he voage nceas es elecic sppy oo nceases Devices called sa bzes ae sed n mos of he domesc appliances lke Ts o fidges o sab ize volage.

Why does votage pay a sg nfcat roe n power trans msson?

 l o s have head o he em volage a some poin. B how many o s know wha exacy i s? Les y o ndesand wh an example I wae has o pass hogh a hose  needs some oce om behnd doesn i? This oce in he conex o elecic powe s volage. So echnicay volage is he name gven o he elecc oce ha cases eecons o ow

16

A ranforer oage is meased in nis of vos and he eqpmen sed o he ppose s caed vomee. The em voage was named ae an Ialian physcs Alessando oa. el Me 

seen ha even a hgh voages above  1 0 K ess energy is os n ransmsson. Ye anohe peciariy o AC eecciy s ha volage can easly be changed om high voage o ow and vice vesa. Ths in rn makes i siabe or long dsance ransmsson  ni ke DC . Aernang cren is aso known o be capable o powerng eecrc moos. Ths i s sel o hghend applances lke eigeraors eevi sions compes ec.

Why do e ue AC up ply in our home?

 naly

dec cren was sed or powe ansmission  was ony n he 1 950s ha people ealised he meis o aenang cen over he oher. Alhogh he wo ae sed oday aenaing cren s more acceped woldwde I is sed o bigge appiances as we as in hoses Le s see why One o he main ea sons or havng AC or domesic pposes is ha i cases vey low wasage o power I is SORY OF ELECRICIY

 '  : �

••••••   . •• •

••• • •• • • ••  •  ••



 .  •

AC - Gapca Repesentaton In erms o saey oo AC s pe ered o DC powe. I is or hese reasons ha mos conies in he world avo AC han DC power.

What i high oltage direct current?



high volage diec cen (HDC) s a ansmisson sysem ha ses diec crren or ransms sion o elecric power in large qani

17

tes. Or in other words t is a technology used to transmit eectric ity over long distances. HVDC is aso caled a power super highway or electrica super highway. We have seen that alternating cur rent s preferred to direct current for varous reasons ncudng financial To address ths as we as other dif fcuties HV DC can be used as they are less expensive and suffer lower electrca losses. In ths technology eectrcity s

Overhea anon ne transmitted through overhead trans misson ines or submarine cabes. Accordng to expes the advantag es of HVDC nclude lower nvest ment cost long dstance water crossing controlabity ower losses etc It also causes lower environ mental impact compared to AC It was in 1 2 that the frst long dis

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Wa of Cuents In the late 1880s there was a rvalry between Thomas Edison the developer of direct cur rent and Nikola Tesla who developed the ater nating current This fight over supremacy of cur rents is popularly known as the War of Currents. tance transmisson of eectric power was dem onstrated usng drect current in Germany In th e 1 930s the technolo gy was further deve oped n Sweden and Germany The modern form of HVDC aso uses this technology. The Ro Madeira i nk in Brazi is the longest HVDC link n the world The ength of this lnk s 235 klometres. e Me Wy

Why i it aid that lightning i one of the major ource of electricity?

L ghtning coud be attactve to a ew and scary to otes but t is deintely a phenomenon that sts ones cuiosity! How many o us know that t is a powe ul bust o electrcty that appens very quicky durng a thunderstom? Techncay ightning is caused by an electrc chage in the atmosphee t is known to contain miions o vots o eectcty Lgtnng can occu inside o between the clouds ets see how ghtning happens Wthn the tu ndercouds up n te sky thee ae bts o rozen randrops that ub aganst each othe. Ths coision creates an eectc chage. As t contin ues te cloud ills up wth eectric chage. n top o the clous te pos

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tvely chaged protons om and at the bottom negatvely chaged eectrons. Snce opposte charges attract ths esults n a new charge bud ng up Ths chage concentates on the g ound under the coud mostly on thngs that stck up ke mountans ta trees eectc posts and even peope.

Benan rankn

Why i it aid that Benjamin ranklin tudied electricity a great dea?

B enjamn

Fankln mly beeved that electrcty and

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ghtnng had cose smla tes. One o hs nventons was the ghtnng od a smpe rod attached to the top of a bud ng. The od was meant to po tect fom the houses destuctve oces o ghtnng. As the electc chage rom ghtnng stkes the rod t woud conduct the charge hamlessy nto the gound savng the house and ts occu pants Frankn made a descpton o ths nventon n 1 753. He s aso credted to have coned tems lke battey conducto electrc shock etc. It s beeved that Frankln began hs expements on eectcty n 1 746. Two yeas late he created a multpe pate capacto whch he called an eectrca battey The capactors wee wred together sequentay to stoe moe charge than one aone could Ths heped to poduce a bgge dschage of statc electrcty Fo hs contbutons to the study of electcty Benamn Fankln receved the Roya Socetys Copey Medal n 1753 el Me Wy

Benan ranns Ke Experen A Panng

Why wa Benamn ranklin kite experiment an mpoant one?

B enamin Frankin conduc ed he amous kie experimen n Phladepha USA. The experimen was done o unde sand he mysery behnd lghning and eecrcy Le s see how i ook pace The inspiraon for he kie expemen came fom Fank ns convicion ha lighnng and eecciy had close sm STOR OF ECTRICT

aries. To pove his he wen o wh hs son on a dak afer noon on June 1 0 1 752. They aached a silk sing o he kie and ed an iron key o s en d. Then, hey ied a hn me al wre fom he key and inse ed i ino somehing caed a Leyden a a conaner o sorng eecrical chage. Franklins idea was o y he kie no he sormcouds and conduc eleciciy down he srng. Laer, when ighning sruck he kie Frankn moved his hand owads he key. Guess wha happened? A spark omed and Fanklin e a shock B uckily or Fank lin he was sandng on an insulao keepng dy unde a

Dint expect this much hgh votage

oo to avoid the dange o electic shock Howeve with this dangeous expeiment it was poved tha ghtnng was eectical n naue

Why  it aid that elec tcty can be found in ome fhe?

 ecc

Ees ae eshwae pedatos ound in the shallow muddy aeas of the Amazon and Onoco ves n Souh Ameica. They often live n sagnant wates They possess enomous amounts of eecticty ha can possiby knock of a age hose o even kil humans t s said hat the eectic dschage om ees can be stonge han 500 vots They ae also known o have

chage is something hat s seen eveywhee in he Uni vese even insde ving hings. Some ishes o nstance have a supis ng amount of elecicty n hem like the eecc eel.

Eecrc Ee

Lgtnng Facts Te ear  ligtning is cmmnly knwn as astapbia, smeting wic many  us ave Te science  ligtning is called ulminlgy 22

aound 6000 cels called eecto plaques that can poduce eeciciy Snce eels have vey poo eyesgh hey emt weak electic signals fo navgaton to ind a mae o pey. But when they spo a pey song shocks ae given to stun them Ohe han eels many ishes incuding shaks lampeys and cat ishes have the abty o geneate electic ields aound them el Me Wy

Why i it aid that ou body ha electricity in it?

J st like the curious case of

eectric ees the human body oo produces eectric signals. Did you know that? We  eveything that we do is made ossible and controled by hese signas running al hrough ou body. We aleady learnt that every obect in the universe is made up of atoms and so is our body. The fow of eectrons in it is what we cal electricity. Lets take an example When the brain orders our hand to hold a dooknob or touch a book thee is electricity carying messages from one point to another. But unike an eecric circuit these eectrons in ou body ae not taveling aong a wire Instead the eecic chage ju mps from one ce o another in a very fast manner unti it reaches its destination. In sho everything in the uman body depends on elecica signals. Hence a beak down in the system can have serious impacts incuding creating hea probems and even stokes. SORY OF EECRCIY

But since thee is so much of electric chage jumping around in the body do not think of it as a power house Scientists hod that the human body can generate ony 10 to 100 milivolts of electic chage Quite stange isn't it?

Why i it aid that the ECG and EEG are o impoant equipment ued for meauring electricity in the human body?

 Go, it int have a bain



and G are two tems we often hea n medical contexts. An G or eectroencephalogam is related to one's bran and an CG o eectocardo gram to one's heat. An G is a tool for measung the bran's electical actvities. It is a test to check the patterns and ocaton of electr cal actvties happening n the ban. Smal meta dscs with wies ae stuck to our head to send signals to a computer As the test goes on the bains electrca actvity over that

 

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peiod gets recorded. Through this test doctors can confirm f the person has any problems eated to ban actvties. ectocadography on the other hand is the process of recordng eectica activity n one's heart ove a peod of

Eectrocog

o  !U  

el Me Wy

te. For ths test electodes o eta tabs are xed to the skn on the sholdes chest sts and ankes As the test begns the eectodes detect tny electca changes on the skn that ase o the heart sces nctionng de to the heatbeat. Thogh the eectrocadio ga the docto gets to kno ore abot the heat and ts health.

ho. It happens in the sae place and n clea skes th ot a sond. This spot as ths decared a Wod Het age Site by the USCO. Lcky Catatbo ghtnng s not destctve lke othes Rathe t s help  Catatbo ightnng povdes a spectac a sght Scentsts say that ths natral phenoenon s

Why i Catatumbo ightning regaded a a tange phe nomenon?

L ghtnng s not aays a scay phenoenon. At east or the peope in enezela t snt. Ths is becase o the Catatbo ghtnng or the eveastng sto that they have alost everyday! Catatbo Techncally ghtnng is an atosphec phenoenon that happens n othen enezela hee the ver Catatbo eets th Lake Maacaibo. The pecliaity o this ight nng s that it appeas 260 nghts a year  0 hors pe day and p to 20 tes pe SORY OF EECTRICTY

EEG esponsibe o abot  5 per cent o ozone prodcton on arth. Hence the natve peo pe are very pod o it. Athogh the easons behnd Catatbo lghtning ae st debated soe expets beeve t cod be a eslt o ethane o Lake Maracaibo.

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Why i ball lightig a trage electrical pheomeo i ature?

B all

lightning is an unex plained natural phenomenon that happens very rarely. It appears as a gowng ba d ur ng thunderstorms folowng a lightnng strike It is sad that these irebas shne too brght y and can be whte ble, ye ow orange or red in coor. hey vary in sze and form; from that o a pea to the size of a smal bus. Accounts of bal lightnng have been recorded for the past ew centries. Accordng to wtnesses these firebas move n an unpredictable and fast manner folowed by smoke that forms spiras arond them Beeve t or not they can even enter buidngs through doorways or wndows travel down corrdors and even navgate ther way to cer tan ponts. hey make hssng noises and sometimes  oud ones too And all of a sdden they dsappear he reason behind the or maton of ba ghtnig s nknown and there are many

26

theores taking about the same. ven though there are many expanations for ths phenomenon none is accept ed wdely.

Sgtng of  gtnng   

Greek Phiosopher hales f Miles is kw  e he fis pes  cdc a expime  eleccy aied y ig piec es  ame He did his ad 600 B.

atmosphere. Appearng ike ire the spectacle o St. lmo's ire is seen manly on ta  and ponted strctres ke ightning rodschimneys aircrat wngs etc. The gow comes aong wth a sond becase o whch i s oten consed wth bal ghtning. Let's pt it cleary wth the same example o a ship. There is a dier ence o votage in the atmosphere and the sea. Ths cases the ionza tion o gases srronding the ship's masts whch n trn reslts in a gow. This s what the saiors mis took as a mrace drng thnderstorms.

What  St. Elmo ire?

he rst accont o St. mo's ire sraced a ew centres ago when saiors spotted a bright gow arond their ships drng thnderstorms. hey believed it was somethng spernatral and this beie contned to be so nt scentsts came p wth their ind ngs. In act St. mo's ire is a phenomenon that s simlar to ightning. It s a orm o pasma cased by potential derence in SORY OF CRICY

t.  re

In most cases sptes ae wtnessed by those n fght above storms. Bt snce they appea fo a vey short ti me  the spectace s often missed This phenomenon s known to have been occrng fo centies its st that no one cod really ecod t. In Jly 1 99 scientists at the U nive

Why ae pite another trange eectrica phenomena in nature?

 prtes

ae a natra phe nomena that is related to eec trcity They occr above thnderstorm cods givng ise to a variety of visal shapes that glow in the nght sky Scentists believe that spites happen when neta ly charged clods dischage some eectrcty to the gond. In short spites are rare large scae electrica discharg es occring above thnder storm clods that appear as attactive visals Sprites have a reddishorange color in the pper region and bsh ten dris that hang below

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Coour ge of  Spe sity of Minnesota accidentaly caght a sprte on camea. Years ater on Api 30 20 2 some astronats captred a ed fash of sprte which was then sed by esearchers and peope acoss the world to stdy and esearch  M 

Why i an aurora conidered to be the mot fantatic electrica phe nomenon on Eah?

n aoa s a dispay of cooed hs ha occ naay in he nih sky. I s manly seen n hih ade eons ike he Acc and he An acc. When hey happen in he nohen ade he effec is also caled he ohen Lhs o Aoa Boeas. When  occs in he sohen a de  is efeed o as he Sohen Lihs o Aoa Asals. Scienss and winesses say ha aoas mosy appea ike cans ha exend in he easwes dec ion. They also happen o be he bhes and he mos dsincive kind. Dependin on he aide hey shne n diffeen coos ncdin be vole ed bih een by ed ec. Reasons behind he fomaon of aoas ae sil debaed. Accodn

Te sewng acne fan kettle and toaste wee te frst fo doestc tes to be powered by electrcty  o one of he heoies he effec s cased by chaed pacles fom he sn ha neac wih he ahs amosphee. Many myhs and eends ae aso b aond he pesence of aoas.

Auroa

Why i it aid that a battery i the mot popular ource o electricity?



battery is a devce that stoes eecticity n chemical form inside a closedenergy system. Long before the nvention of electrical geneators and grds batteres proved to be the ma n

I have a ight weght mobile

sorce of electicty and st contine to seve ths p rpose Thee are batteies in dffer ent shapes Some are very small lke the ones sed n wristwatches o smart phones and some are as big as those sed n cars and tcks At the extreme thee are hge bat tey banks that are the sze of rooms Al batteies have three parts an anode (the negative side)  a cathode (positive side) and an eectolyte a qid or gel that contans eectcally charged paticles caled ions When connected to an exte nal ccit the ions interact with the othe two and a chemcal eacton takes pace nside the battey. This eaction ests in the generation of electric cent. This is how batteies fncton e Me Wy

and provide eecrc power o al appances n our house incuding mobie phones apops flashighs ec.

Why i it aid that there are o type o batterie?

B aeries can be broadly divded ino wo prmary and seconday. Prmary baeres are sngeuse baeries ha s hey can be used ony once. Afer ha hey should be dscarded They canno be recharged Quie a few nonrecharge abe baeres are used in our day ife. This incudes baeries used in oys radios remoe conros fashighs clocks ec Those baeries ha can be recharged and reused are called

SORY O EECRICIY

eand is e only on y in e wod wee eeiiy s poded eniey by enewable soes seconday baeres Through eecric curren hese baeres can be recharged. Secondary baeres can be seen in many devices ncuding ce phones MP3 players ec Ye anoher exampe can be seen  n cars and rucks Did you know ha here is a leadacid baey ha works every me we sar a car? This is how he car ges ener gy o run he lighs and radio when he engine is no runnng. The baery in he car is recharged whie we drive. 

Besides leadacid there are other batteries that can be recharged. This includes the nickelcadmum battery thumion battery nckemeta hydride batteres etc

Why i it aid that the hitory o the bae i intereting?

B atteies ae devces that have been helping mankind or a long time But nobody knos exacty hen they ere invented. An account o the ealest battery came in  93 fom Baghdad The story goes that hile constucting a ailay line in the cty orkes uncoveed a pehstoic battery. xpets said that the battery belonged to the Pathian mpire and as at least 2000 yeas old! Luigi Galvani in 76 as con ducting an expeiment hen he acci dentally touched a dead rogs legs th to derent metas. Suddeny the muscles o its egs contracted He thought it as because o anma electicty'. But hs fiend and fello scentst Alessandro ota didn't agee. He guessed that the same eect ould be poduced i card board as soaked in salt ater instead of a rogs eg  So he stacked coppe and zinc discs separated by a cloth and soaked them n salt

32

Lg Galvan ater He connected ires to either end o the stack To his surprse t pro duced stabe curent Thus in  00 olta

FACT

Nickl admium "n a  is It is said that a nickel cadmium rechargeale cell phone atter is capale o polluting ,00,000 litres o water. That is three such at teries can pollute an Olmpic pool!

invented the voltaic pile ', the first true battery that produced continu ous and stable current Ths is believed to have ad the foundation for he modern battery

was an eectrochemcal cell deve oped by the ngsh chemist John Danie n 1 36 The cell ofered a onglasting source of power Lets see how the cel works Dan iel cell, consst of a copper pot filled with a copper sulfae soution n which was immersed an unglazed earthenware container fled with su furic acid and a zinc eectrode. The earthenware barrer which is porous, alows ions to pass through, but keeps the solutons from mixing. This cel produces current like a voltaic cel does, but with more eff ciency. It soon became the industry standard for use A voltage of over one vot is produced by a Danell cell. o get a lttle more voltage, one has to increase the concentration of the soluton n which the eectrodes are dipped

Danie Ce

Which i the irt practi cal-purpoe bae?

he Daniell ce is per haps the first practica purpose batte ever t SR  EECRICI

33

What i meat by eectromag netim?

 ectromagnetism is a basic force of nature t is the crea tion of a magnetic field from the movement of eectrical charges. The basic characteristics of this force can be best defined through the example of a cop per wire When electric current is alowed to pass through the wire it can attract or magnet ize pieces of iron or steel near it That is the electromagnetic force causes the attraction as

well as repulsion of electricaly charged particles There are two basic con cepts behind eectromagne tism. The first one is that any moving charge produces a magnetic fied because of its movement. The second one is that a moving magnetic field

Hep me

An Eecc Moo can cause current to flow into a conducting loop This means if there is a moving bar magnet near a coi of wire that is con nected to a meter, it can detect the current flow. e Me Wy

Why i the hito o the eec tromagnetic theo interet ing?

he history o electromagne tsm cannot be complete without a ew names Lets take a ook at a ew o them In 1820, Hans hrstian

Has Chstian Osted

Ande-Mae Aee

Orsted a proessor at the Uni versty o openhagen arranged an experment or his students He wanted to explain the heating o a wre by an eectric current and his experments on magnetic property. or this he used a compass neede mounted on a wooden stand Suddenly he noticed that every time the electrc cur rent was switched on the com SORY OF EECRICIY

pass neede moved. Orsted was surprised and kept working on this or months to study how t happened However he was not successul. But this experiment was taken urther by another physcst n France named AndreMare Ampere Through hs

Mchae Faada

study he ound out that wires with parale currents attract each other whereas those with antiparalle current repe . He concuded that eectricity can be governed by two sets o orces eectric and magnetc A ew years ater Michael Faraday and Joseph Henry independenty ound out that it is possibe to produce current � 

A Magev Ta in a condctor by chang ing the magnetic field arond it. This theory heped in aying the fondation of modern day electricity. However earlier eectricity and magnetism were seen as two different properties It was in 165 that James Maxwel pbished his work A Dynamical Theory of the Eectromagnetic Fied', demonstrating the connection between the two forces.

36

Why i it aid that many o the phe nomena that e itne in our daily lie can explained y electo magnet ic orce?

 lectromagnetism is a phenomenon that works behind almost a forces on Earth Perhaps the ony

Goo news Eetomagnetsm exsts.

Te Me W

FACT Maglev Magnetic evitation or Magev tains functon on very strong electromagnets that carry the tan on a cushion of magnetic repuson.

exception is gavity Its ifuence is such that expets believe moden ife is un though the eectomaetic phenom enon. Let's ty to udestad what this means. ake  the case of an eectic fa. Its moto woks on the pincipe of eectomagnetic inductio, which keeps it otatig on and on. This in tur, makes the  bade ub of the fan to otate, owig ai. Anothe exampe is that of a loud

speake It is the electomagnetic foce that is esponsible fo the movement of the coi inside This in tu, esults in the poduction of sound that ca be head ove a long distance. In the same way, amost all appli aces that we use in ou daily ife, including motos, gadgets, T, adio, computes, wok  on the pinciple of electomagnetism. In shot, al foces involvig inte actio between atoms can be explained in tems of eectomagnetism that occus between the eecticaly chaged atomic nuclei, and eectons of the atoms

Diagam of the Magnetc ield ceated by Electricty

What Is an electromagnet?

A n electomagnet is a device that

can ceate a magnetic fied if e ecticity is allowed to pass though it. We can undestand it bette by

comparing it with an ordnary magnet. In normal magnets magnetic power is aways pre sent. But n electromagnets the magnetic power or field depends on eectric   It can be turned on or off using a switch. Likewise the strength of these electromagnets can also be increased by increasing the amount of electrc cur rent There are different parts for an electromagnet. It conssts of a coil of wire made mainly of copper and a piece of met al. The wre should be wrapped around the metal piece When

In the Right Wa Accordg to Flemg's rgt-ad rule f oe olds s rgt tum frst fger ad mddle fger at 90to eac oter te mddle fi ger wll dcate te drecto of te duced curret

Wia Sgeo's Eecoage electric current is allowed to flow nto the wire a magnetic field is created around the coiled wire and the metal gets magnetised. This is how an electromagnet is created Today almost al equipment that we use have electromag nets in them

Why i it aid that the intro duction o electromagnet wa intereting?

he first recorded discovery about the relaton between

8

  

electicity and agnetis was ade by Hans Cistian Osted in  820. Duing an expeient, he noticed tat te needle on is opass pointed to a diffeent iecton, wen a battey nea  was tu ned on In  824, Wilia tugeon nvented an electoagnet. t as ade of a osesoesaped piece of ion, wapped t coppe wie. He found out hat wen cuent was passed houg te wie, t attacted he pieces of ion, and wen he electic flow stopped, te agnetisation ended too By te  830s, te U scenst Josep Heny ipoved he design of te electoag

Somethng happene to ths compass

net He used an insulated we, and placed thousands of tu ns of wie on a singe coe his ade a big cange! Wit tis attept, electoagnets gained oe populaity

Jaes Cek Mae

What i meant by electomag netic radiation?

ee ae diffeent waves of igt and enegy that ove aound us ey coe n the fo of eat in te atospee, o adiation fo space, o in any ote fo ese enegy waves ae coonly known

Heinch He as electomagnetc radiaton Tey ave eectic as el as magnetic caactestcs Te scientific definiton gven to ts by expets goes as fo os  te enegy tat s propagated tog fee space o a materal medm n te form of electromagnetc adiation . Ote tan visbe gt, elec tromagnetic radiation incdes rado aves, micoaves, infared aves, ltravoet rays Xays, and gamma rays Tey ae classfed on te basis of ter freencies or aveengts Te fact tat te electromagnetic adiations ae

40

eated to electromagnetism as pt foad by a fe scientsts in te past Te exstence of electromagnetic aves as fst pedcted by te cotts pyscist James Clek Maxel In is electomagnet ic teoy tat e pt fot in 1 864, e sad tat ligt is an eectromagnetic dstrbance in te form of aves A fe yeas later Geman pysicst Heinrc Hertz appied Maxels teores to prove te existence of eecto magnetic aves

What  iductio?

eectromagetc

 n ts smpest terms, electro magnetc ndction can be defned as te pocess ee a condcto placed in a cang ing magnetic fed cases te podction of votage across te condcto. Tis, n tn, cases or indces an electic crent. Many electrical devces tat e see daly ork on te pincpe of electromagnetic indction  A common se of tis can be seen n electrical genera tos, transformers, indction e Me 

Mchael aada ookes, usical instuents et e concept of eletoagnetic indution was put fo i n te ealy 1 830s by te Englis pysicist Micael Faaday He conducted any expei ents to study te idea In one of it e used a coil of wie a peanent agnet and a device to detect voltage in te ie Wen Faaday passed te agnet toug te coil of ie e saw tee was a voltage induced and teefoe uent too But it soon disap peaed wen te agnet SORY O EECRCY

stopped oving Fo tis, Faaday ade a few obsevations. e ost ipotant one was tat te inded votage is te esut of a angng ag neti fed. In ote ods, Faaday dscoveed a way to pode eletial uent by usng te foe of a agneti feld e voltage ndued is knon as te eletootve foe o ef. Faadays fndings ed to a law linking eletcity and agnetis known as te Faa days Law of Eletoagnet Indution

Okay It's working.

Why i it aid that Thale o iletu played a major role i the hito o electricity?

aes of Miletus is an potant figue in te istoy of electcity It is sad tat e discoveed

hales of Mets static electicty aound 600 BC. tatc electcty was fst obseved wen abe ubbed wt ana fu, got caged,

42

and attacted lght obects suc as dy leaves o bts of staw Even tough ote peope ay ave notced ts befoe, it was aes wo fst ecoded hs findings But haes ave neve dentifed it as statc eectcity. At tat tie agnet is was aso confused wt static eectcty. Late t was poved tat te foce tat wok between abe and anal fu s nothing but statc eectcty. haes oe was eakable because he was te fist to ecod is findings egadng static eecticty ales was bon in te city of Mletus aound the d 620 BC He was a pilosope, and astonoe and te one wo conducted the ealest studes i n eecticity ales fndings wee ecoded but none of te suvved to oden tes.

Why i it aid that the machine hich produced tatic electricity o the irt time a a turig point i hi to?

Otto von Guecke was a Gean scentist, and nvento who lved between 1 602 and 1 686.   

He is cedited to ave ade any inventions at a tie wen tee wee not any esouces to efe to. One of t is te eectostatic geneato, known to be te fist one eve ade. It was descibed as a uge supu bal, ounted on a pole inside a glass globe. Wit te elp of a and cank, te ball was otated. As a esult te ball ubbed against a pad, geneating spaks Tis was static electicity a penoenon wc tey could not den tfy ten. But te device becae faous and was

used fo ate expeients wt electicty In 1 672, Gueicke found out tat electcity poduced toug s eaie expeent coud cause te suface of te sulpu bal to gow Te concept of eectostatc epuson was deonstated fo te fst tie in stoy toug Gue ickes book

Why did the elay make hito ?

e

Oo o Gecke SORY OF ECRICIY

splest definiton fo te elay s tat it s an eecti caly opeated switc. e device s used wee t is nec 

essay o cono a cc by a opoe sgna o hee a nbe of ccuis have o be conoled by one sgnal. Relays ae conoled by elecc cen, agneis o epeae. Thee ae o ypes of eays elecoechanica and solid sae In he foe, conacs ae opened and

The eay as invened n  835 by Joseph He ny. He ceaed  n ode o ipove his vesion of he eecical elegaph. Reays ae sed fo any pposes. Thei applicaion can be seen in dga copes elephone exchanges and aoaon syses.

Why i it aid that Stephen Gray played a major role in the hitory o electricity?

 ehen Gay as an Eng-

Joseh Hen cosed usng a agnec foce Wih solid sae elays, sching s done eleconically Eecoechancal elays ae geneal ppose elays They ae oe coon becase hey have oe cos and can sich fo AC o DC h eal ease. 

ish asonoe ho ade signfican conbions o scence. These nclude his expeens ih conducon insulaon and elecosaic indcon. One of his expeiens as done using a gass ube. Gay obseved ha hen he glass as ubbed h a dy hand o dy pape,  obained elecic chage. As a esl i ataced a feahe o he glass as ell as he cok ih hich  as cosed. The cok as in fac used o keep he dus ou he n no in se. Fo he expeien, Gay concded ha he attacve   

vtue' is passed fro te tube o te cork. To clear is doubts, Gay oceeded wt a sila experent. Tis tie, e attaced an ivory bal to a ece of wood, and inserted e oter end of te wood into e cok Once it was done, e onfired tat attraction and epulsion passed to te ball at too stronger tan tat on e cork. Gray observed tat substances like silk do not conduct eectricity. And tat Eart was soeow responsibe fo con

I hink his lolipop is a beer conducor.

Sehe Ga ducting eectric carge away fo te body For is electrical experi ents , tepen Gray eeived te first Copley Meda institut ed by te Royal ociety in 1 731  However ost of is works went unacknowledged, and e died as a poor a n.

Why was the introduction of Leyden jars a milestone in his to?

 Leyden jar was te first

device tat could stoe electric carge It was a gass ja wit eta fol wrapped to its inside and outsde surfaces. Te jar

would be patly filled wt wate and ad a we unnng into it toug te top pat of te ja Tee ae two naes involved wit te invention of

in te wate inside te ja In te 700s, Benjain Fanklin studied uc about ts and poved pove d tat cage wa w a s stoed in te glass Hence te late vesions of Leyden jas ad just etal foil wapped inside and outside te glass Tecnically a Leyden ja is te pototype of te oden day capacito wic ae used in alost all electonic euipent today

Why wa the invention of the lightning rod a major break· through?

B enjain Fanklin invented

Bej Be ja ai i ak te a One is Ewald G von Kleist a Gean invento wo is said to ave accidentally ceate ce ated d it in 1 745 Te ote is Piete van Musscenboek of Leyden, Holland, wo discoveed ee d te sae sae tin ting g in 1 746. Te latte inventon spead toug te wold uickly, and tus Pete gained oe populaity fo te invention invent ion At fist, it was tougt tat te electic cage was stoed

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te ligtning ligtning od od n 1 749 A ligtning od is a etal od

Resse ees to the mesu me suee o dut dutyy volved  pss pssg g  elet uet though  oduo   W

A ighning ighn ing Rod

though the building o tee. Thus, the stuctue can be saved fo eectocution. Hstoans say that ghtnng ods ee used in ancient ties and ee paticualy seen in the i Lankan king do of Anuadhapua thou sands of yeas ago. Hoeve, i n the oden age, age, t as as Benan ankln ho intoduced the idea to the old. His a as to ceate a tool that could save sa ve peope fo the danges of the natua phenoenon Though a sees of expei ents incudng the faous one using kite, he ceated the ankin od

ounted on top of elevated stuctues like a buding tee, ship etc. It is electcally bonded th a ie ith the gound o eath eath  though an electode. uch an obect potect a stuctue hile ghtnng stikes. The dea behind it is that that hen ightning  ightning hts the buldng o tee t ill stke the od. As a esult the eectic po e fo ightning ll be con ducted to the gound though the ie nstead of passing SORY OF EECRCY

47

el ectica elect ica ene enegy into into echa  echaninical enegy by eans of eectoagnetis The oto he ceated though the expe ents was piitive, but t paved the way fo late inventions n  822 822 Bitish phys physici icist st Pete Baow invented the fist device to be poweed by elec toagne to agnets ts know knownn as Ba Ba  ow's Wheel.

Moz Mo z Jacobi Jacob i

Why wa he inroducion of he elecric mo moo orr im i m poan?

 n eectc oto is a device

that convets electical enegy into echanical enegy t woks on the pinciple of electoagnetis The fst electica oto is known to have been invented by a cottish onk Andew Godon, n the 1740s Hs oto was a spe electostatic device Alost a centuy ate, Bit ish scientst Michael Faaday expained the conveson of 8

An EEec ecc c Moo Moo A decade late, Bitish scientist Wilia tugeon deveoped the fst achne to be un on dect cuent. A few yeass afte yea afte that, invento invento Moitz Moi tz Jacob ceated the fst eal otating electic oto that deveoped a eakable echanica output powe.   

Fank Julian pague was te fst to ntoduce a constant speed electc oto All tese ave togete con tbuted to te advanceent of engneeing tecnology n te wold

Why wa the introduction of the fuel cell a miletone

Fue ces ae devces tat geneate eectic cuent toug cecal eactions To put it bette a fuel ce uses ceical enegy of ydogen (o anote fue) to poduce electicty in a clean and eff cient anne. Its ony poducts ae eectcity eat and wate and ence it is cean. Tee ae a wde ange of applications fo wic fue cels can be used includes Tis t  a n s p o  t at i o n  eegency pow e back up ate ia andlng etc Copaed to ot e tecnologies fue cells ave any advantag es Tey ae oe efficient and

Wla Gove ave lowe eissions Tat is tey do not et dangeous substances ike cabon dioxide o ai polutants as te ony poducts ae wate and eat. Yet anote advantage s tat

Lets forget a1l power problems. Use this fuel cel

fe ces opeae n a sien anne. The hisoy of fel cels began wih he Wesh physicis i Wa Gove. In 139 he deonsaed he fis cde fe cels. Ahogh any peope have ied o wok on he concep of conveing checa enegy ino eecc powe, os of he wee nsccess f de o lack of esoces The fs sccessfl fel cel was developed by he Biish enginee Fancs Bacon in 1932 sing hydogen oxy gen an alkaine eecoye and nicke eecodes.

Wla Stae

h i i ai ha h invn in  h anm wa a nin pin?

e W'z d Most o Edison s nentions ourred in his bortory n Menlo Prk. In 878 he nmed the lb the  nention tory  This gret sientist himsel me to be known s  the wizrd o Menlo Prk

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 ansfoe is an eecica device ha woks on eeco agnec ndcion o ansfe eecca enegy beween wo o oe ccs. I s sed n a wide ange of powe appances o incease o decease voage. We see ansfoes in aos evey cy. They ae    

used to convert igvoltage electricity fro ncoing power lines, to owervoltages Te first known transforer was developed in he 1 880s ince ten e device as played a key role in transission of power. Tere are anly tree naes nvolved wit the inven on of transforersOtto Blaty, Miksa Deri and Karoly Zipernowsky Tey are known to ave desgned te first ransforer in te early  880s. Te first reiabe coercial transforer was built in 1 885 by Wiia tanley ince ten e device as payed a key role in te transisson of power.

hy i the introduction  the trnitor  mjor urning point in hito?

o put it siply, a tran

sistor is an electronic coponent tat can do wo dfferent jobs. It can ac as an aplfier or a SORY OF EECRICY

switc , depending on te need. As an apifier a transistor does te job of boosting current Tat is, it takes in a tny input current at one end and produces a bigger output cu rrent at te oter end t was at te Bell Laboratories in New Jersey tat transstor was de

A Repca o the Fst asisto onstrated for te first tie Tat appened on Deceber 23 1 947 Willia ockey, Jon Bardeen and Walter Brattain are te tree persons credited wit its invention n 1 956, tey were awarded te Nobel Prize n Pyscs for teir researces on seiconductors and teir discovery of te transistor effect" 5

hoas l Edso

Why i the Edion eect an impoant miletone in hito ry?

n

one of is expeents, Toas Ava Edson dscov eed tat eectons can fow fo one etal conducto to anote, toug a vacuu Ts discovey was late naed as te Edson Effect oete in te ealy 1 880s Edson and is tea wee wokng to find a lgt bub faent Tei cabonised baboo filaent did wel  but even

52

so, cabon deposits wee seen insde te bulb afte ous Tat was wen e noticed tat te cabon cae fo te end of te filaent wc was attaced to te powe suppy. It ooked as toug it was flying toug a vacuu onto te wals! Edison eaised tat tee was electic cage flowng not just toug te fiaent, but toug te evacuated bulb as wel Atoug Edison was igt about te fow, e coud not find te eason beind it He oved on to ote expeients Late, t was poved tat Edison, wit is expeient ds coveed te basis of te vacuu tube And te odified ligt bubs wee late used to contol te fow of eectons toug vacuu 

Why  it aid that the amplifier and triode changed the hito of electricity?

 n electonic aplfie is a tool tat can aplify o ncease te powe, cuent o voltage of a signal. It could be eite a    

signals. t is a fundaental fo of vacuu tube developed by te Aecan nvento Lee De Foest. He ad only a little undestandng of ow te tube woked. Howeve, te dscovey ev olutionised electical tecnoo gy and laid te foundation of electonics It also ade pos sibe adio boadcasting taking otion pictues, and countless ote applications

ee De Fores sepaate piece of euipent, o an electcal cicuit witin anote device, but in genea apfes ae used in alost all eectonc euipent tat we see aound Tey ae patculaly used in wieless co uncatons and boadcasting Befoe te aplifes wee ntoduced, ecanicaly cou ped icopones wee used o seve te pupose in tele pone epeates. n  906, te tode was nvented t was te fst elec onc device tat coud aplify SORY OF EECTRICITY

A ode 

Hhre Dav

Why i  aid ha Humphrey Davy' conribuion are unique?

he story of the invention of the eectric bub was very inter esting Even thoug many beieve tat it is Thomas Ava Edison who discovered the light bulb, it was not so He 

played a maor role in te deveopment of te ight bub, and its popuarity. T e story of te ight bulb begins ong before Edison patented the first comercially successfu bub in 1 879. Aessandro Volta's invention of the battery in 1 800, gave inspiration to many scientists One among tem was Humprey Davy He produced the words first eectric lamp by connecting votaic pies to charcoal electrodes It cannot be caled an electric bulb as such It was an eectric arc lamp, and he introduced it in 1 802 It was named so for the bright arc of light emitted between its two carbon rods However, Davys arc lamp wasnt a very practical source of lighting. It was much too bright for use in a home and it burned uicky. But te princi ples behind tis arc light were used througout te 1 800s and many took inspiration from this invention Te Me Wy

Why is it said that Wiliam Staite and Warren de la Rue's cntributins are remarkable?

D ffeet

kids of electic amps wee veted by mas es i te past Te Eglish iveto Hum pey Davys eecic ac lamp was oe suc ceatio that made geat chages  te field of electicty ad lgtg. Howeve, te ac amps wee ot flawess. Te bggest dis advaage was that ey wee ot ft fo pactical use They emitted oo muc of ligt ad

I have an eetal amp

ist in the Wod Joseph Swan's house has a histoica impotance. It was the fist in the wod to be it by a ight bub and aso by ydoeectic powe.

also, but out quckly Neveeless, the picipe of ac lamps was used ill te 1 900s by vaious ivetos fo deveopig electic ligts ad bubs Amog tem wee Wae de a Rue ad Wlliam Staite. I 1 840 e Bits scietist Rue developed a ligt bulb usig coied patium fiamet istead of coppe State, o te othe ad, had bee wokig o iceasig the o gevity of covetioal ac lamps. I 1848, e developed a cockwok mecaism. Toug tis he was abe to eguate te movemet of te cabo ods used i  the amps at eoded vey q uickly. 

Joseh Wlso Swa

Why i it aid that Joeph Swan, along with hi contem porarie made a igniicant change in electric blb?

 nother person who made

significant contributions to the making of the eectric bulb is Sir Joseph Wison Swan. Swan was an Engish chemist. D uring the  850s and  860s he conducted many experiments on bulbs using carbon filaments Most of them failed because the vacuum pumps used in those times

56

were not good so they cou dnt remove enough air from the amps Besides the amp deposited a dark layer of soot in its inner suface. This obscured the  ight In  878 Swan demonstrated an improved working lamp t had a better vacuum and car bonised thread as a fiament The method of processing was such that the bulb avoided ear y blackening. Soon ater the demonstration Swan was granted a UK patent. Ater that ight bulbs were instaed in homes in England In  880 he received a U S patent too For his contributions Swan was knighted in  904 The same year he also received the prestigious Hughes Meda instituted by the Royal Societ of London.

Why i it aid that Edion contribtion to the develop ment o the electric blb i nmatchable?

We

saw that during the  800s many inventors have worked hard to develop an effective light bulb But the most successful among these

Te Me 

hoas  Edso invetors was Tomas Alva Ediso. Edisos serious researc to maig a practical ca descet lamp began aroud

Do not distub Hes checkng the ife of hs bulb.

 878 He wanted to invet a safe yet ceap electric ligt tat could eplace te ealier ones. Betwee  878 and  880 e conducted many experments, wit carbon fla mets platium and oter metas In  879, e success fuy tested a bub wit a car bo filament tat asted  3. 5 ours Te followig year, Edison ad is team discoveed tat a carbonised bamboo filament coud ast over  200 ous Tis mared te begiing of commercially made ligt bubs in  880. As we now tis is just oe of te many inventions made by Ediso Tus, Edisos contibutios remai unparaeled ad, for is tireless wor e was igt fully described as one of te greatest ivetors.

Who invened ligh bub wih ungen filamen ha are widely ued oday

 cietsts

ad ivetors ave used a number of fla mets for icadescet bu bs i te past But today te

57

most popula one is te tungsten fila ment It was Wiia David Cooidge wo deveoped a metod to manu factue tungsten fiaents in 1 91 0 Te biggest advantage of tungsten was tat it ad a ig melting point, and was abe to witstand eat and coosion Tat is exactly wat attacted inventos to it. esides using inet gases inside te bub inceased its luinescence. As yeas passed te element was used in ote laps too incuding alogen fuoescent, mecuy vapou etc. Tungsten is peaps te most duabe type of fiament used in bubs even today It is said tat Toas Alva Edison imsef knew tat tungsten would pove to be te best coice fo filaments ut in is day, te tecnolo gy and maciney equied to poduce te wie in fine fom was not avaiable.

How i a orecent amp dierent rom an incandecent amp?

s you may

know incan descent and fuoescent ae two types of igt bubs commonly used fo vaious ligting applications. Incandescent igt bulbs ae olde, but ae sti used in ou ouses. Tey

58

dso's 

Enmity of equals It is believed that there

was a rivalry betwee oseph Swa ad Thomas Alva Ediso The two geat ivetors had ot met or spoke t each other before the ivetio f the icadescet lamp   

Icadsct ght  come  the orm o a glass sphere with a very thi ilamet isde It s the tugste ilamet that we mostly use ow ad t is surrouded by a iet gas I these bulbs lght is produced by heatig the metallic lamet utl it starts to emt light. A luorescet bulb is totay deret. It is a glass tube coated with p hosphorous, cotai ig mercury vapour. Whe the gas iside is excited these lamps SOR OF EECRICI

produce ght. Ulke icadescet ghts they come  dieret shapes ad sizes here are may other diereces betwee icadescet ad luores cet lghts other tha these he or mer has a ow eciecy ad short e. Fluorescet amps have very high eicecy, oger lie ad are also eergy savig hey are said to last  0 to 20 times loger tha a icadescet bub Howevermay experts say that uorescet lamps pose threat to health ad evromet. his is because o the mercury cotet i them Also, uorescet amps are more expesve tha the other type.

59

Wat makes compact fluores cent lamp an energy saving option?



compact fluoescet ligt (CFL) b ul b o amp is a type of fluoescet lamp tat s desged to epace icadescet lamps ey ae ow by diffeet ames as compact fluoescet ligt o eegysavig ligt o as compact fluoescet tube. CFLs come i diffeet sapes ad foms ad ae pimaly ow fo tei effectiveess ad log life e mode spial saped CL bulb tat we use today i ou ouses was developed by Edwad Hamme i te late 1 90s Altoug tee ae diffeet easos wy people use C Fs te most impotat featue of tese ligts is tei abiliy to save eegy t is said tat tey cosume  pe cet less eegy compaed to icadescet lamps Compae to odiay igts CLs ae moe expesive but tey last loge Oe ca use tem f mots togete but ot oiay bulbs

6

Deep Inside Huge electric currents re generted rom the Erths ion coe tht lies deep inside These currents cuse  mgnetic eld to be ormed tht extends to outer spce r beyond the Erths surce

 EASURE i RI  

_  



Why is a ammeter impoat?

n

ammeter s an nstru ment use to measure the flow of electrc curren n a crcut I measures current n terms of amperes, whch s the unt of curren. The spee an force of a curren can be measure usng ths nstrument. In he pas, the nstrument rele on the Earth's magnetc fel to ake he reangs of current. Bu as technology mprove better ammeers

Ths ammeter shows you have hgh urrent

Aee were esgne an evelope Ammeters are mostly use n scence laboratores Oher than scentsts, electrcans also use ths nstrument o check the electrc crcut There are smaller uns of reang to amperes namely, mllamperes an mcroamperes. These are measure usng mllammeters an mcroammeters respectvely There are two types of ammeters analogue an gal In analogue ammeers there s a neele that pons to the reang In gtal ammeters, they are splaye gally.

61

lso voltmeters tt c be moted o  trsformer d oter ge devices. Yet oter vriety is  volt meter tt se mplfiers  them  Sc meters c  mes  re very sml or tiy voltges of microvolts, or eve ess. l

Why i the votmete a impo tat equipment?

 voltmeter is  istrmet tt mesres te voltge betwee two poits i  electric crcit. It c be coected to  crcit by joiig its positive d egtive wires to were te voltge is Wth sc  rrgemet, the istr met is sd to be prllel to te electrcl circit. A voltmeter c be sed for my prposes. or stce to check weter tere is y more electricity left i  bttery I  loge votmeter, te piter idictes the mbe r of volts   digitl voltmeter he redig wil be displyed digitlly. Tere re

62

What i a galvaomete?

 glvometer is  too tt mesres te flow of electric chrges trog  wire. Tis bsic device cossts of  col plced i  mgetic fied. It c be sed for detectig d

Etmoog The tem galvaomete was deived om the ame o the Italia electicity eseache Luigi Galvai, who discoveed the piciple o og galvaoscope i 1791. He had oud out that the legs o a dead og would move f it eceived a electic cuet   

What i a multi meter?



Dga Galvaoee compng smll electrc cu ents The de o glvnometers re known to hve deveoped om n obsevton mde by Hns Orsted n 120. He d ound out tht te needle o  mgnetc compss delects ner  wre tht s electc current pssng troug t But t ws Johnn Schwegger who bult te st senstve glv nometer n the sme yer. Gl vnometers snce ten cme to commercl use. A glvnometer cn be used s n mmete, s well s  voltmete. By connectng  shunt n ple to the col, t cts n mmeter, nd  the shunt s connected n seres wt te glvnometer col t becomes  votmeter SOR OF EECRICI

mut mete s n nstu ment tt mesues te vot ge, curent, nd resstnce o n eectcl devce. Also known s  VOM (VotOhmMllmmeter) tey re very useu n provdng ed mesuements o detectng ults wth ccucy. Te st mutmeter ws nvented by Dond Mcde  Brtsh post oce engneer who ws unhppy wth te need to crry seprte nstuments needed o te mntennce o telecommuncton crcuts. Hs nventon ws the nstument tht coud mesue

Digal Mliee 63

ampees vots ad ohms ad was amed the avomete The devce s commoly used by electcas ad othe expets to toubeshoot pob ems o appaces motos ccuits powe suppes ad wig systems. They could use the device o batteies swtches powe souces etc o measug o dagosg . Mu ltimetes ca be aalogue o digtal aogue mu lti me tes ae cheape but the eadigs ae ot as accuate as the dgtal metes. Recet digtal mut metes ae advaced eough to measue extemely ty dieeces o uctuatios

 tme f a elf evauatn

64

   

\ 



Ohee

Why i the ohmmeter an impoant meauring equip ment?

  ohmmete is a electca stumet used to measue esstace o a coducto. Resstace as we have aeady see is the opposito oeed by a substace to the cuet ow i the device The u t o measuemet o esistace is i ohms hece the too to measue t s called a ohm mete e must kow that evey devce has a esstace lage o smal. Resstace i co ductos ceases with tempeatue but deceases i the case o semicoductos. epedig o the appica tio thee ae mico ohmmetes mili ohmmetes ad

  

mega ommeters used A micro ommeter measures extremely ow resistaces wit g accuracy wereas a mii ommeter measures t e same ad cofirms te value of ay eectrical circuit A mega om meter measures arge resist ace values ere is a device caed Flue micro ommeter It is used to measure votage curret ad test diodes

ha i an ocillocope?

  simple terms a oscillo scope is a type of equipmet tat provies visual images of vayig electrical quatties Tat meas tat ts ma fuctio is to grap a elctrical sigal as it cages over time Most oscilloscopes prouce a R F EECRCI

two dimesioa grap sow g time o te xaxis ad voltage o te yaxis. Te sigals produced are potted o a grap. Tere are a um ber o app catios for wic osclloscopes are used Most of te geeral purpose istrumets are used for mateace o electroc equipmet ad laboratory work It s a importat too or

Oscioscoe desigg or repairig electroic equipmet. Specia pur pose osciloscopes are used for aalysig a automotive igitio system or to isplay te waveform of te eabeat as a electrocariogram Osciloscopes ca be ivide ito two igital ad aaloue gtal oscilloscopes are portable uits tat are replacig te aalogue oes

6

Why is Coulomb's law oe amog he basc laws of elecricy?

M any scieniss have in he pas,

Chales Agst de Coob

Fly Chaged

ied o sudy he feaues of chaged paices and he foce hey exe on ohe chaged paices u he eason ehind his emained a mysey unil he Fench physicis Chales Augusin de Couom pu foad his heoy on he same. Couloms aw as i is nown all ove he wold descies he eleco saic ineacion eween eecically chaged paicesThis law was fis puished y Couom in 1 83. es see wha  says Suppose hee ae wo chaged paicles. Wih hese is ceaed an elecic foce f he chages ae songe he foces hey ceae will e songe oo. This is he asc idea ehind he law. Cou lom also found ou ha eihe aacion o epulsion acs along he lne eween he wo chages A decade eaie iish scenis Hey Cavendish also made smia osevaions, u he did no pulish hem. So, mos of he cedi wen o Coulom alone.

  

Geog So h

Why is Georg Simon Ohm considered o be  gre sci enis?

G eog Simon Ohm was a Geman hyscst who formuated the Ohms Law t states that cuent flow through a conducto is directly roortional to the otenta dffeence or votage, and invesely roortonal to the esistance. The aw was  otant ecause it marked a suc cessful start to the analyss of eectrc cicuts. In  827 Ohm uished hs ook tited The Galvanic Cir SORY OF EECRCIY

cut Investigated Mathemat cay in which the Ohms Law fst aeared. Athough it was ater teated as an imortant wok that infu enced the theory and aca tons of eecticty the ook dd not eceive enough accet ance when t was ushed It s sad that Ohm esgned hs ost as a teache fom Jesut Gymnasum of Coogne du e to this A few yeas ate, Ohms Law stated getting noticed and Ohm was arecated In  84  the Roya Society of London awarded him its es tgous the Coey Meda con sdeng hs contruton. The hysca unt measuing eectca resstance ohm was named after him.

Why is Frdys lw impor n?

he

concet of eectici cannot e comlete wthout Faadays Law of induction. It descres how changing magnetic felds can cause electc curent to fow in a conductor. The workng rincle of electc motors transfomers

67

generators are al based on Farada's Law o Induction Farada dscovered electro magnetc induction n 1 831  He ad conducted man exeriments beore concud ng is teor He exerimented wit magnetic fields tat staed te same and realsed tat te do not induce current.

Faadas Lee Ten e exerimented b cangng magnetc elds and saw tat te nduced current and voltage

irst o its Kind rance and the United Kingdom wee the irt nation to ppot the widepread development o electic vehicle he it nown electric car wa built in 1837 by chemit Robert Davidon o Abedeen. It wa powered by galvanic cell

68

Te Me 

Faadays d sovey of eetomagnei idu o did o eeive mu aeptae fom se sts we it was intodued. Bu Sottis setis James Clek Maxwe eaised its mpoae and used he ideas as the ass of his uaniaive eleomagnei eoy.

s an eeomagnet phenomeon The euaions fomed fom these aws ould gve an explanation o may penomena aoud Fo nsane ow hai stands on ed we oe emoved a ylon sweae

ae o Maxwe

Why is Maxwes equa tion known as the fou dato of cassca eectromagnetism?

M axwel

euaions efe to a se of fou euaons tha desie e eaton and popa gaion of ee ad maget fields Tey ae amed afte he Sotis pysiis James Cek Maxwe who made signfian onti uions o u fy te theo es eeiy of magetsm and lgt. e eay fom of these euatios was pulished etwee  861 and 1 862 and it poposed ta igt SORY OF EECRICIY

ow a ompass neede poits not a e ime how a powe staton tuine geeaes eetiiy e. Togethe ey oud aso desie te tansmsso of ado waves and te popagato of igt. Hene Maxwels euao alog wi e Loetz foe aw is said to fom e foudaio of lassia eeomagnetsm. Loentz foe aw deses e foe ating on a movig point hage  i te pesene of eleomagnei fields

69

What are power tation?

A Ncea Powe Pa

 powe staton s a place where eecticity is produced on a lage scale o distibution. It is aso caled a power pant o powe ouse. The electrcty generated here, mostly in several thou sand watts is transmtted to powe grds throug power lines It is rom tese gids that people get eectcity or omes scoos, businesses etc. A maority o the powe sta tions in the word burn ossl ues to generate electricity.

I want to build a ower lant

This ncudes coal, o il  and nat ural gas. Tey ae caled thema powe stations. hee are also plants that use nuclear powe instead. It is sad tat over  1 pe cent o the words power is poduced by nucea power statons But tese days, there is an ncreasing use o enewabe esources ke sola wind, wave and ydroeectic powers o eectricity generation At the centre o almost al powe pants there are AC geneators o altenatos Te machines convert mechanica powe to eectrcal power In 2 Edison establshed te Peal Steet Station a power pant that provided eectic lightng in Manattan. The station an untl destoyed by e n 190.

  

Wy i i aid a e iory o ydroelecic power aion begin in London?

H droeecrc power p as use e orce o alg waer o geeae eeccy. Is oe o e saes sources o eegy a s also rela ble ad ceap. Soe o e earles ydoeecc powe plas were se up  ad aoud Lodo.   e 1 0s Egls dusrals W a George A srog bul oe sc pa a Cragsde  Egad. Ts was per aps e wolds rs ydoeecc powe scee.  sed waer ro e akes o s esae o powe e geeraor I 1 2 a cea sao was bul  Goda g Eglad, usg ydo

Wlia George Arsong elecrc power Ts e  was o povde see ad oseod lgg o e pubc. B s pojec eded up as a aue. However ay ydroelecrc pojecs wee coceved all over e word by e. I s sad a  201 5 ydro pow er geeraed 1 6. 6 pe ce o e words oa elecrcy A os 1 50 coures ave ydro power pas oday w Ca beg e arges producer o ydoelec rcy

Cragsde 71

What is meant by the Wa of Cu rents?

he War f Currets, was the Energy roducers Together, fossi fue power plants and nuclear power plants provide approximatey 80 per cent o the electricity needed for the word 

 

term used t refer t the dispute betwee tw briliat ivetrsThmas Alva Edis ad Nika Tesa.  happeed twards the ed f the  ceury, whe here arse a uesti ver which was beterdirec r ateratig curre Eds was he brais behd he devepme f DC, which ra c tualy i a sige direc   the early years f electriciy, DC was regarded as he stadard. But it had a prbem; it cud be easily cverted  higher r lwer vtages. Tesa srgy beleved hat alteratig curre was a sui t ths AC, which he cdevelped cud reverse its direci ulike DC, ad

 

72

e Me 

could also e conveed o deren voages using an elecrica ransorer. I ade ossile long disance elecrcy ranssson oo. However, Edison saw Tesla's arguen as a hrea o hs work. He hus saed of a ulic caaign yng o discredi AC. The an rea son for he caaign was ha Edison did no wan o ose he royales he had een earnng fro his DC aens. Bu i n sie of a he effos Edison ade,  was Tesla and hs AC ha won in he end Today eecrciy s ainy owered y alernaing curren.

Why i i ai ha hermal power a ion are common?

 heral wer saion is where

A Thera Powe Pa rciy. I s he os con venonal, and coon source of elecrc ower. Les see how  works. A hera ower an urns foss fues ike

Obsessions SebanAmercan nven tor Nola Tesla was nown to ave an obses son or te number 

hea energy s used o generae eec SRY  EECTRCITY

73

coal, o, ad ata gas to podce steam. The steam ths omed, ceates a pes se that sps the tbe sde the plat. lectc powe s geeated by these spg tbes The advatages o a thema powe pat s that t ees ess tal cost, ad less ad compaed to othe powe statos. The e sed  oss el s aso cheap May co tes  the wod deped ma ly o themal powe o eectcty It s sad that aod 40 pe cet o the wold's pow e s made ot o ossl es Howeve, thema powe pats have bee ctcsed o the poto they case, de to the age amot o smoke ad cabo doxde emtted Ths s a case o gobal wamg. Besdes, the oveall ececy o a thema powe stato s beow 30 pe cet.

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Chies o a hea Powe Pat

Wha make hydroelecriciy moe accepable han he elec riciy produced by hermal poer aion?

s we saw eale, hydoe lectc powe pats make se o the oce o owg wate to geeate electcty Thee ae may easos why expets hold that hydoelectcty s moe acceptable tha the oth e Oe o the most sgcat advatages s that hydoelec

trc ower ants do not reqire terma ants. Besdes these, any fel for ower rodction ydroeectric lants are known Tey only need water, a to faciitate rrigation of farms renewable sorce of energy. and reventing floods. Thermal ower stations need Hence, arond 1 50 contries fossil fels ike coa natral in the word se ts technologas o etc., to fnction gy for ower generaton. ince no fe is req red te cost of electricty rodced by H  electricit prdced i ydroeectric ants is also hdrelectric per tat? somewhat constant In te s we know, t is fowing case of oter kinds of ants, t deends on te cost of fels  n water that creates te energy te internatona market reqired to generate eectrcAnoter imortant factor s ty Wonder ow it works? ollton. Hydroelectric ower Wel, there is a hge amont ants do not brn fel; ence of energy created from te fa do not case oltion ether. ing of water. Ts energy s The heated water tat comes arnessed by forcng t trog ot of them treatens aqatc a ie, wch is caled a enlves too. stock. At te end of the e Hydroeectrc lants also ave longer ves comared to A Hdoeecric Power Pa



Soa Cs Sola cells ae sed to powe potable devces lke calclatos They ae also called photo voltac cells

there is a trbne pope er So when wate fows thogh the pipe t eaches the propelle and tns the blades of the tbne. hs spns an eectic generator Hence as ong as wate s flowing the generato wi be spn and there wi be electcity hee ae many three ways n which hydoe are lectric pants designed he most common type folows a stoage system. o pt t clearly thee is a dam sed in this system. It slows the

76

fow of a rive and stoes the water in a reservoir above t When needed a portion of the water is eleased nto the iver fowing below the dam. he presse ths ceated from the fal of wate spns tbne generatos ying beow. om this is created hydoe ectcity Yet another s the rnoftherver system Hee trbnes are spn by the natra fow of the rver. he thid type foows the pmped storage system. his is simar to the fst type of stoage system Bt the dffeence is that t ses pmps to pmp the sed wate back into the resevoir.

How o olar power plan work?

s the name sggests soa pow er plants se snght for power pro dcton. here are two different technologies sed for sola powe podcton these days sing photo votaic pants and sola thema sys tems Photovoltaic cells o PV cells po dce eectc crent when exposed to lght hey are aso caed soar ces hey contain sicon a natra ly occring eement fond n sand. When snlight hit silicon there hap pens a chemcal reaction As a reslt eectons move and eectric crent

  

s prodced A gop o PV, or soar cels ceae a soar pane A nmber o solar panels orm a solar aray, and hey geneae solar enegy In soa hemal sysems, sngh is coleced and concenraed o prodce h gh em peare hea ha is needed o

I my own olar ower an

 \  - � 

A Soa Powe Pan geneae eleciciy A he sysems have sola energy colecos wh two componens a reeco ha cap es and ocs snlgh ono he eceiver In he sysem here, a hea anser lqid is heaed and cclaed n he receiver I s sed o podce seam The seam is hen converted o mechancal enegy n a rbne, whch powers a geneao o prodce eecicy

Why i it aid that the wind and de are the bet way o podce electric power?

The wnd s a maor sorce o enewabe enegy ha is also sel o geneae power Yo ms have seen windmils in

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e lie  n teevs. They e set   ms  we genetn. Altgh tey k like ns wndmills wk in jst the  site wy. n ns eectcty is sed t mke wnd bt  wndmils wind s sed t mke eecticty. ets see hw they wk. Wen te wid bws, it tns the bdes  te widmi l Ths in tn sns  genet side nd dces eecticity A sgle wndmil c genete nly  sml mnt  eecticty. ence we cm es bid wind ms wth  lge nmbe  wd t bnes.  mny cntes cldig Denmk d Ptg wid we cntbtes gey t we dctn

Yet the m  enegy cmes m ce tdes whic gn cn be sed t dce eectcty. Jst ke wid tbnes, thee e td tbnes t. Tey e tned by ce cets. The sinig t bes e cnected t devces tht genete eecticity. ee gi te cess d dcts e se, s tee e  hml emisss mde.

Why i mi and bima mch e ed rce  electricity generatin?

Osmtic we is te eegy

tht cmes t  te die ence in slinty betwee se wte d es wte This

Wd bes

eergy ca e haessed to geeate eec tcty. stage Souds doest it? Let's see how ths happes. Whe we separate esh wate from sea water y a sem permeale memae we ca see that the fesh wate moves though the memrae to the sea water. This happes y a pocess caled osmosis. It meas the move met of somethig om a ess cocetrated soutio ito a cocetated oe. There is a pressure created y the process o osmosis. Ths pres sure comied with the pemeatig flow ate together turs a hydrauic turie ad produces electricity. Statat the Norwe ga eergy m was the wod's first test plat that haessed osmotic power. Experts ote that there are may advatages to ths kd o powe poducto ove SORY OF EECRCIY

An ofhore wind fam of Statkaft others. Howeve the iggest chaege this techoogy aces is the cost Osmotic power pats ae just too expesive to stal. Yet aothe reewale eergy s iomass a uel that is deveoped fom orgaic mateias like cetai cops maue forest deis etc. I iomass power plats waste is ured to poduce steam that us a tuie producig electricty.

Wha i mean by he erm eecric pwer ranmiin?

 ectic powe tans-

mission means the transe o electic power rom one place to anothe in arge uantites. Typicaly, this happens between a powe pant and a substation situated near a popu at ed aea A substation is whee votage s tansomed rom high to ow o vice versa using tans omes When power is transmtted om substa tions to consumers, the

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 Sub Staon pocess s caled powe distibution. Nomay transmssion takes place at vey high votage, li ke   0 kV o above. This s because o the lage amount o powe nvolved in this Ove ong distances, eecticity is tansmitted though ovehead power transmisson ines. But n places that ae environmentally sensitive, or whee thee s vey high popuation transmission takes place unde gound They have hgh installation cost and opeationa mitations, yet their maintenance cost s lowe The network o power stations, tansmission lines, and substations is together known as a tansmission grd.

  

 de elecrcy cme  ur me?

Fom

the momet power s geerated  a pat, it goes though varous stages befoe reachg our homes. Lets see how power traves. Fom the eec ticity geeatig pats curet s set through trasformes to icrease the votage, so that it ca be pushed oger distaces. Eectrc power the eaches a substatio Hee the votage gets owered, so that t coud be set to smaer power es.

Resistos to Resist Rsisos in an cric circi a sd o rdc cr ow or o dvid Voags SRY  EECRCY

Fom thee, t traves though vaous distibutio ies ad eaches your eghbouhood whee smaer tasfomes reduce the votage so that you ca tae safe power to your homes. Fom the tasforme power is cared though service dops, or smaer overhead eectrica es to your homes. It aso passes though the mete' staed i the house that ca measue how much powe s used by the famiy. The curet moves staight to the sevice pae, where fuses protect the wires isde the house fom over oadig. Keep  mid that chidre shoud ever touch this pae ! It is fom here that power fay moves to the switches ad outets a over the house.

1

What i mant by ovrhad pow r lin?

Ovrhad

powr ns ar sucurs or lcic pow ransmssion and dsbuon acoss larg disancs. Thy also mak h chaps mhod o ansmiing powr In usua cass ovrhad pow r lns hav on or mo conducors suspndd by owrs On o h major dus o hs pow i ns s o manain nough spac or claranc bwn hs ngsd conducors and h gound n od o avod dangr. Ths days pow ins can b oprad a voags o 765,000 vos or vn mor bwn conducors Dpndng on hir ang o voags ovrhad powr ins can b cassi d as low volag mdum voag hgh volag xa hgh voag and ua high volag. Howv hs pow lns ar xrmy dangrous and on has o kp a sa disanc om hm Unk houshod pow cods ovrhad powr lins a no nsulad. Evn   looks ik an insulaon i migh b a wahpoong maa.

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Why i it aid that tran formr play a major rol in lctric powr ditribution?

 ransorm s an cr

ca dvic ha ansorms ciciy rom hgh o ow volag and vc vrsa.  is an imporan componn or pow ansmsson Ls g o know why. W saw h procss hough whch cic pow achs ou homs Whn lcrcy avs om a powr plan i coms n a

A High Volage Transmsson Towe

A diode is an electric coonent ade of seicondctor ateri als like siicon gea ni or seeni It has two eectodes in it- the anode and te catode •

A Step Don ansforer

 

vey hgh voltage. his s becase the votage ro the pant s stepped p' by transorers beore they ae tansitted he voltage has to be inceased becase eectic poe has to trave very ong distances, and that too, ith inia oss o energy. We shod kno that energy s ost n the process o oe tansission. Bt  the voltage s high, enegy loss old be o SRY F EECTRICITY

Bt do or hoes need this knd o voltage? Absotey not Beore the poer reaches hoses, the votage has to be oeed, or stepped don his s hee tansorers agan becoe ipotant hey step don votage o hgh to o

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ELECTR CTY I N H OMES hy i he eeri meer an im an equimen in hue?

 lecic mees ae devces ha we

commony see n houses and oces. They ae used o measue he oa eecca enegy consumed by he aliances n a house o oice The devces ae insaed by he eecc owe comany ha sules eec icy. I you ake a close look a hese mees, you can see a ew dgs. They denoe he numbe o uns o eeccy ha has been consumed so a. Ou eeciciy bi deends oally on his eading. Thee ae deen yes o elecc mees avaabe in he make. One s he eecomechanical mee, whch s mos commonly used n ou couny. I has a magneic mealc dsc aached, which oaes, deend ng on he owe assing hough i. The ae o his oaion decides he eading on he mee. Then hee ae eleconic mees ha ae oula n ces. In hese, eadings aea digay on he dis ay ixed on he mee. The newes n his eague s he sma mee. They ae eeconic

84

An Eectric Mete mees, bu hey have an advanage added These sma mees ae conneced back o he

utility (which provides us eectricity) through the interet. Hece, no official will have to come in perso and take the readigs. The readings are sent through the interet, which makes the job easier.

awatts. A megawatt is equivalet to oe milion watts! The term watt' was amed after James Watt who devel

What is the measuring unit of electricity?

E lectric power is always represented i terms of watts (W) or kilowatts (kW) A thousad watts together make a kiowatt Watts describe the rate at which eectricity is cosumed during a specific period Take the case of a 1 5watt LED bub. t draws 1 5 watts of  power at any moment whe tured o Lets ook at other exampes to understand the cocept better. The power ratig of a typical incandescent ight bulb used i houses is between 25 to 1 00 watts To produce a similar amount of ight, fluorescent lamps consume 5 to 30 watts and LED amps use 0.5 to 6 watts Comig to power statios, a pical  power station that uses oa to geerate electricity pro uces around 600 to 700 meg STORY OF ELECTRICIY

An LED

B

oped the steam engine. Watthour is quite different from a watt. It is a measure of electri cal eergy equivaet  to a power consumption of one watt for oe hour

The fit electric ligt in India was lt in Kolkata, on Jly 24 1879. It was demonstrated by P.w Fleury & Co 85

Demand Drivers Ida s the wod's thd largest poducer ad outh largest cosumer o electrcty

It s a problem that aises when two o more wires in an electrical cicit that ae not spposed to come in contact toch each other This action is immediatey folowed by a very high crent fowing throgh the cicit. This can rest in a lot of dangers lke sdden fire destrction of the components in the circit o melting of insaton Sometimes thee can aso be an electrical exposion or what s known as an ac fash

What  meant by a ho crcit?

 hot cicit is a tem we hea often and it is something that is dangeros fo sre Let's see what exacty a short cicit s.

Nothing . but a short circuit

Scary isnt it Howeve there are fat protection devices like crctbreakers and fses that can detect a short circit.

Why i he e an impoan eqip ment?

s we saw ealier a fse is a

devce that s provided in an electrical circt to protect the applances connected to it from damage It s a safety tool that imits crent in a crcit.

  W

The n there are blade type fuses that come in a plasti c body with two metal caps, to be fitted in a socket. These

Cicuit-beakes Structurally, a us is a sho ic o wir mad u o lmnts lk zinc, cor, silvr, auminium which hav high sistanc, and a ow mlting oint. n cas o ovrhating du to xcss curnt, th us tnds to mlt and sarat. It thus vnts i outbraks and aso otcts humans om ctic shock. Fuss, in gnal, a usd in a tys o lctrica and ctronic alications. Dnding on thir uss, thr ar dint tys o us s avaiabl On is th caidg us, which is usd to otct lctrical aiancs k motos, aiconditions, rigrators, ums tc., hr high voltag rating and unts a ruid ORY OF EECRICIY

uss a mostly usd in auto mobis o wiing and otction rom short cicuit. Anothr catgory is o sttab uss. Thy can b usd multi tims without bing acd. Such uss ar sn in nucar systms, or in arosac systms.

Why i i aid he inrodcion of he elegraph, elephone, and lodpeaker are a clmi naion of elecriciy?

gah,

a tchnology dvlod in th aly 1 8 cntury, voutionisd longdistanc communication. It was a sim ctical circuit that tansmittd ctric ignals ov a wi, btwn stations

Teegap qupent 87

l eephoe Through the telegap nes, messages coud be sent back and fot as busts of electrcity. It was te connection between eecticity and magnetism tat led to this pathbeaking nvention. By the end of te 1 9 centuy, another invention su facedthe teepone It was a different and advanced devce tat mproved communcaton between long dstances. In a telephone, an eectrc cuent cares te sound. Here again, te invention followed the prncipe of eectromagnetism . Anote mpotant devce that works on te same principle s te loudspeaker It con vets an electrical signa fom devces like a rado, or teev sion nto sound. For ths pur

88

pose, te sgnals ave to be connected to an electonic ampifier Generally a loudspeaker is built usng a coi of thn coppe wre, a still paper cone and a ccua magnet Wen electrcal signals ae passed tough te coi of copper wre moves back and foth. This, aong wth the magnet, cause te paper cone to vbate and eproduce sounds. Taking into consideraton te above mentoned devices, as wel as other equipment, one can say that no invention in recent tmes has been compete witout eectricty.

one with the Wind Inda s credted wth havng the ffth largest wnd power capac t n the world Wnd power acconted for 9 per cent of the contrs total power capact n 01516.

 v

e Me 

Why i it ai that eectrcity itribution i ierent in eve  country?

Th lccal sco of any couny in h wold dnds mainy on is conomc sys m, and oics adod y s govnmn. nc, h who ocss of ow oducon and ans mission in a couny nd no  h sam as ohs In

som of hm, gnaion, ansmssion and dsiuon of lciciy s don y a govnmn conod oganisaon. Bu n som ohs, vay ownd comanis w hav shas oo. Jus lk h oaion, h voag and funcis fo ovding ccal ow o aiancs oo, diff fom couny o couny In India, 50  and 230 vos of ow s dsiud fo domsc and ndusa u oss. ouns lik ungay, Iay, Indonsa, Gmany, Fanc, and Russa oo, foow h sam an Bu h USA and anada hav a dffn schm of 1 20 V and 60 . n Paksan, Ian, and hna  is 220 V and 50 , and n Jaan  s 50/60  and 1 00V. hs mans, vy couny has dffng us gading dis uon of ow

89

Wy i i aid a India i a gian in e producion of elecriciy?

he powe seco of nda is known o be one of he mos divesified and powefu ones n he word Souces of eecrcy geneaion hee ncude conveniona sources ke coal nau a gas, oi , lgnie, hydo and nuclear powe, and aso nonconveniona

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Thera Power Plant at Kota, Rajasthan souces ike soa, wind, agrcuua and domesc wase. The couny has wnessed a vey fas growh n eecricy geneaion since 1 0. In he year 20 5, he couny became a powe supus naion ha possessed huge eecc generaion capaciy Bu many vllag es in Inda do no have powe con necon even now. By md201 6, I ndia's powe gene aion capacy crossed he 00,00 MW megawa) mark, incudng

90

Gifte Wth te nagratn f a dedcated slar plant the Ccn Interatal Aprt mted (CIAL became the wrld" s fir ly slar-pwered aprt n Augst 18 015 moe han 42,848 MW enewable enegy souc es such as sola and wnd powe plans. This means, he couny's enewable energy sec o s considered very mpoan. Abou 65 pe cen of he eeciciy produced in India is from hermal power pans Moe han 20 per cen of he powe comes from hydroeec c powe plans and  pe cen fom nucea plans. The es s fom aernae souces. e Me }

Why i it aid that India' grid management y tem i niqe?

 ower grd efers to an nterconnected net work or dstrbutng electrcty to consumes. It was n the 1 960s that nda began utlzng the grd management sys tem on egonal bass. The ower grd system was then geogahcay dvded nto fve egons or bette management These egons arenorthern eastern, west ern, noth eastern and southern grds They were establshed to enable the transms son o surus electcty between states n each egon. Towads the 1 990s, the Indan government stated annng o a natonal gd As a esut, the above mentoned

egonal grds wee nterconnected. In October  991 , the frst nterconnecton was made, between the noth easten and the eastern gds. A few years later, n 2003, the western grd got connected wth the above Ths rocess oowed n the

gh Votage ectrc l n the maaas later years as wel. The nothern grd was aso nterconnected n August 2006. In Decembe 203 the remanng grd southern was connected to the centa gd n a synchonous mode. Thus, the am to bud One NatonOne Grd One Fequency was acheved

Wh is the use of renewable energ impoant?

hr ar many rasons why rnwabl nrgy s mportant for th word and ts futur Th man advantag of ths nrgs s that thy ar fr of polluton Rnwabl rsourc s ar way canr than fossl fuls bcaus thy dont pro duc toc wasts Nt, th rsrvs of ths nrgs ar nvr ndng unk coa, gas, ol or nuclar Hnc, thyr sourcs namd rnwabls Powr producton from fuls and othr nonrnwabs dmand a largscal mport of ths rsourcs at h gh prc s Aso, thr cost dpnds on th ntrnatona markt In th cas of rnwabl rsourcs ts not ndd as most of th nrgs dpnd on th Sun 

9

Eofend opons fo Powe Geneaon hr ar many countrs that dpnd largy on rnw abl rsourcs For nstanc, Dnmark, UK Scotland and rand mak grat us of wnd nrgy Dnmark whch has bn a ponr n th fld, gts around 42 pr cnt of ts powr from wnd plants And thr ar countrs k Chna, and Inda that us of hydro powr for lctrcty, whch s qualy saf

How do we save eectricit?

B y now w shoud al know that lctrc powr s vry pr cous and has to b savd. Thr ar of cours many ways to do that. Lts ook at a fw of thm.

  

The irst and oremost step is to mae sure that any appiance is turned o when not n use For ighting, you coud use LEs or CFLs nstead o incandescent bulbs And  ts daytime, try to mae use o the day lght nstead o other ights. They coud very well serve the purpose! The next thing to remember is that eectrca appances shoud never be e on standby Its a major waste o power A TV consumes 1 0 wat power n standby mode. I you are usng an air condtoner, mae sure the doors and windows are closed, so that the power is not wasted. But any day, ceil ng ans are recommended instead o cooers and air condtioners. The appiances that account or a big chun o your electricity bil are rerigerators, air condtoners, wash ng machnes etc. And as they get oder, power consumpton too goes

up. So, old appiances shoud be replaced by energysavng modes on time, so as to save power These are some o the methods you can try to save power n homes.

Frst Electrc Tran The first electrc train in India ran on February  195 on te Harbour ine between Bombay's ictoria Terminus and Kurla SORY OF EECRCIY

93

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anya Jan C lass VI   Army Public Schoo, Ambaa Cantt, Hayana.

ntenational Winne  n the Wil d Vaca Vacati ti on' categoy.

The Natio nal Georgr Georgrap ap hi c Kids recently held a world-wide p hotog rap hy cont contest est for ch il dr dren en , The various various national editi ons conducted separate contests and the i ntern atio nal win ners wer weree chosen from fr om t he firstp firstp rize wi nn ers in va va rious countries One of the I ndia n winners winners  Sanya Jain [12) fro from m H a rya na  has beenn ch ose bee osenn as an i nternation al wi nn er  n the 'Wild Vaca Vaca tion categor categoryy.

           ! !

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al en lo

Mammen Mamm en Matw Manorama Ma Mairam, iram, Manganam Mangan am     Kry Empire In 3d Flr No  19 M Ktta K ttayam yam 6 08 nanr Road Baglor- 5 1 2  K Mammen Mappai ndo Blm L Empir lnfn 20 Mr Mr Rha Rha  Mathw Mathw Mammen, Mammen, Bl Bl E13 E1 3 Wigdon Wigdon Encave Pndit Kauppan Rd, Thevra, hi-682 013  3r lr,  Infanty d Bagalore- 5 1 3 M  Phli 1, Gant d Bangao  1 21 M Amba Mammen &  M. Mamm Mammn, n, 17, Gilc Aven fn n ad  ad Ce Cet t    2,  > 1 C-  03 03 5 Mr  Mammen  GN Ch a,  Nagar 22 M n n Zia Ahoa a Hou Hou  Mou Wardha a Aho C C a ai i 6017 6017 Ktym   6 M  mme 15, Walla Garden 1st    Ammu aew Kandal, Old  Rd, CnnaCn na-   Cngam, oyam  1 7 D M.  Mammen, Mot W 17 Glchris Avenue,   K Mammen Ktyam·   Road Che Cnaj  031   M Mmmen Mmmen No.6 No. 6 Rerde Rerde Rod Rod,, 8   ra Thoma Mou Mou Wadha Wadha tyam  0 25 Mr M Kotupam Ko tupam Chenni 6 0 08 8 Oopti ti Kwdar PO, 9 Thiruvanan M An Kurian hapram695 apram 695  26 Mr Mmmen E E 5 5  Walae Gaden, 1s Se Cena Ce na    10. M Ma Kuria o Mr T Kur 402, kyine Aamen Lrd  Bgo   27 M bcJab, Jab, Flat No IB AUM Apartmen, 26, Rd Nugambakkam Chena- 034. 034.  1  M Sh Mmmen Mmmen No 10, Wall Wall  Garen 1s 1stt Strt Strt Che Ch ena nai i   Mmmen Katam, 4 Crey Se  Ricmond  AndTow, Bangao 5 025 12  Shlpa Mamme C Apartment May Vir, C  F P  New hi· 101 2  P.V nCra Php  Cmr Ha 72, 13. M ilp ilp & Mr hi Philip,  s at Ct Egmo Chena  A31 A g Aplo  Comun NM J   Maa Ka 1&5 Binny Cn n  3 M Marg,  Mumbi4 OI Bagaore   1   Katt Empi nnt ru Flr No 2, 31 Mr Adi 31 Adit t  Mammen Bl E3 Wllingon tr Roa Bangaor 5 001 Enave, P Kppa Rd Thevar K82 013. 15 Mr Prm 15 Prm Mmmen Mathew Mathew,, Manorama Manorama Mandiram Mandiram 32 Mr Va Mmmen Mmmen Mappillai Mappillai No No 6 Rve Rveid id Roa Road d Mtm 6 018 Kt K truram ruram Chea Chea   Mr Phili Philip p &  ia Nanat     mm No.6 Ris  tuam,  Cni·    Fla No A A i plo Fla p lo lomnd, omnd,  NM Jh ag  M 011. 011.  r r Mmm Philip  Chadik PTowe,  17  waty V,  lr Vws 8 old No 3 Co , Chenna   Prthv Avnue, Abirmapram Cena 018 18 M BiD Mw, MANOR,   oll M  Philip,  Cadika, PTower 8 Pnt Kaup Rod T - 013  Chei Chei    V. r  dla tht  giv  ar   te  o my kowlge nd   a: 01-02-201 ulisher

     

Its tme to use a memo card...

Questio of the Mot Why do we foget thing? Oh no!  forgot ts password.

  b: Aman Agarwal,  Sd   q E  teehy@p.i STORY OF EECTRICTY

s we al know our brain s a brlliant magcian It allows us to do amazing tings ke learn multple languages and solve complex matematica problems. ut te very same wizard at tmes, deceves us by forgetting tings Wy do we forget tngs? Scentsts suggest many teories beind tis strange beaviour by our bran Most prominent among tem is decay teory wic states tat our memory sowy disappears wt te passage of time Anoter teory is interference Tis means tat wen we get some information similar to information already stored n our memory, t s likely tat we forget te new information Strange but true

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