1. Rasika Kalupahanage N. dip in tech.(sc.), B.Sc (Science), Pgde (Sc. Edu.), M.Sc (Sc. Edu.)

3. Name of the electrical Equipment úÿ,s úÿ,s WmlrKfha WmlrKfha ku Use Method that electricity is supplied to the equipment WmlrKh WmlrKh i`oyd úÿ,sh úÿ,sh , ,efnk efnk l%uh Electric cells úÿ,s fldaI m%fhdackh m%fhdackh ku i`oyd l%uh Clock Trf,daiqj To know the time fõ,dj oek.ekSu Rice cooker n;a msiskh Head lamp of bicycle md meÈfha bÈß ,dïmqj To cook rice n;a msiSu

4. Sources of electricity úoHq;a m%Nj • Equipment or appliances that generate electricity are called sources of electricity. • úoHq;h ksmojkq ,nk Wmdx. úoHq;a f,i f,i yeÈka yeÈka fõ fõ' ' úoHq;a m%Nj m%Nj

5. Sources of electricity úoHq;a m%Nj • Dry cells / úh<s fldaI • Simple cells / ir, fldaI • Car batteries / jdyk negß • Bicycle dynamo / nhsisl,a vhskfudaj • Electrical generators / úÿ,s ckl hka;%

6. The contents in a dry cell úh úh<s <s fldaIhla fldaIhla ;=< ;=< wvx wvx.= .= oE oE iskala ;yvqj ldnka l+r ridhksl øjH

7. The way equipment generate electricity úoHq;a m%Nj j,ska úÿ,sh W;amdokh jk l%uh 1. Electricity is generated by a chemical process in some sources of electricity. There are various chemicals in them. e.g.:- Dry cells, simple cells, car batteries etc. 2 Some sources generate electricity by rotating or moving them. e.g.:- bicycle dynamo, electrical generators 3 Solar cell :- Equipment that generate electricity by using solar energy 1 wmg yuqjk we;eï úoHq;a m%Nj ;=< úÿ,sh W;amdokh jkqfha ridhksl l%shdj,shla u.sks' fïjd ;=< úúO ridhksl øjH wka;¾.; fõ ksoiqka - úh<s fldaI" ir, fldaI" jdyk negß 2 lrleùu fyda p,kh lsÍu u.ska we;eï úoHq;a m%Nj úÿ,sh ksmojkq ,nhs' ksoiqka - nhsisl,a vhskfudaj" úÿ,s ckl hka;% 3' iQ¾h fldaI - iQ¾h Yla;sh u.ska úÿ,sh W;amdokh jk Wmdx.

8. Cells / fldaI

9. Construction of a simple cell ir ir, , fldaIhla fldaIhla ks¾udKh ks¾udKh lsÍu lsÍu Observations when the bulb is connected Observations when the motor is Connected Observations when the coil is connected Observations when the ammeter is Connected Any other Observations n,anh n,anh iïnkaO iïnkaO l< l<úg úg ksÍlaIKh ksÍlaIKh fudagrh fudagrh iïnkaO iïnkaO l< úg úg ksÍlaIKh ksÍlaIKh lïì lïì o`.rh o`.rh iïnkaO iïnkaO l< ksÍlaIKh ksÍlaIKh weógrh weógrh iïnkaO iïnkaO l< úg úg ksÍlaIKh ksÍlaIKh Tn Tn ÿgq ksÍlaIK ksÍlaIK ÿgq fjk;a fjk;a l< l< úg úg l<

10. Centre zero ammeter ueo ìkaÿ weógrh • An ammeter or a milli ammeter used to measure the current. • Ampere (A) is the standard unit to measure electrical current. • The subunit, milli ampere (mA) is also used to measure small current. • ikakdhlhla ;=<ska .,k úÿ,s Odrdj uekSug ueoìkaÿj iys; weógrh iys; ñ,s weógrh WmldÍ fõ' • Odrdj ukskq ,nk iïu; tallh weïmshrh (A) fõ' • l=vd Odrdj,a uekSu i`oyd ñ,s weñmshr (mA) hk Wm tallh o Ndú; lrhs' fyda ueoìkaÿj

11. Simple cell / ir, fldaIh • Terminal on the copper sheet is considered as (+) ve and the one on zinc sheet is considered as (-) ve in a simple cell. • ir, fldaIfhys ^+& w.%h f,i i,lkqfha ;U ^fldm¾& ;yvqj yd iïnkaO w.%h jk w;r iskala ;yvqj yd iïnkaO w.%h ^-& w.%h fõ'

12. Weaknesses in simple cells ir, fldaIfhys we;s ÿ¾j,;d • Difficulty of using them, because it contains liquids. • Inability to obtain current for a longer period of time • øj wvx.= jk neúka Ndú;h wmyiq ùu' • jeä fõ,djla úÿ,sh ,nd .ekSsug fkdyels ùu'

13. • The illumination of the bulb, the speed of the motor and heating effect of the coil are increased when several cells are connected as above. • n,anfha §ma;sh;a" fudagrfha fõ.h;a" o`.rfha r;a ùu;a" ;ks fldaIhla we;s wjia:djg jvd jeä nj fmfka

14. Batteries / negß • A setup constructed using several cells is known as a battery. • More electric current can be obtained from a battery, than from a cell. • fldaI tlsfkl iïnkaO lrk ,o wegjqula negßhla ye`Èka fõ' • fldaIhlg jvd jeä úÿ,s Odrdjla negßhla ,nd.; yels h' lsysmhla ksjerÈj f,i u.ska

15. Name / ku ku Material of make / idod idod we;s we;s øjH Instances of uses nyq,j nyq,j Ndú Ndú; ; lrk øjH lrk wjia:d wjia:d Dry cells / úh<sfldaI zinc sheet, carbon rod, carbon powder and other chemicals iskala ;yvq" ldnka l+r yd ldnka l=vq jeks ridhksl øjH Electric torches, Radio sets, wall clocks etc úÿ,s mkaoï" .=jka úÿ,s hka;%" ì;a;s Trf,daiq wdÈh i`oyd Alkali cells / CIdr fldaI Metals like nickel and cadmium, alkaline components ksl,a" leâñhï jeks f,day j¾. iy CIdr j¾. Telephones, cameras ÿrl:k" leurd wdÈh i|yd Button cells / fnd;a;ï fldaI Substances like lithium and Mercury ,s;shï" riÈh jeks øjH wrist watches, calculators etc w;a Trf,daiq" .Kl hka;% wdÈh i|yd Lead – acid accumulator (car battery) Bhï - wï, welshqñf,agrh ^ld¾ negß& Lead and diluted sulphuric Acid Bhï yd ;kQl i,a*shqßla wï,h Cars, buses, motor cycles and in rechargeable electric torches ld¾" nia" fudag¾ ihsl,a wdÈh ;=< iy wdfrdamKh l< yels úÿ,s mkaoïj, fndfyda úg mj;s

16. Terminals of an electrical source úoHq;a m%Njhl w.% • There are terminals on an electrical source to draw out electricity • In most electrical sources, there are two main terminals. 1. (+) ve terminal 2. (-) ve terminal • úoHq;a m%Njhl isg ndysrg úÿ,sh ,nd .ekSu i`oyd úÿ,s w.% mj;S • fndfyduhla úoHq;a m%Njj, m%Odk úÿ,s w.% folla mj;S' 1' ^+& w.%h 2' ^-& w.%h

18. Direction of current flowing from an electrical source úoHq;a m%Njhl Odrdj .,k ÈYdj • Note the direction in which the motor turns, and the direction in which the indicator of milli ammeter deflects. • Change the terminals connected to the circuit and observe • úÿ,s fudagrh lerflk ÈYdj yd weógr lgqj .ukalr we;s ÈYdj igyka lr .kak' • fldaIj, w.% udrelr iïnkaO lrñka kej; ksÍlaIKh lrkak

19. Observation / ksÍlaIKh • When the terminals of cells are changed the direction in which the motor turns and the direction in which the indicator of milli ammeter above change. • fldaIj, w.% udre l<úg fudagrfha N%uK ÈYdj fuka u weógrfha lgqj p,kh jQ ÈYdj o fjkia úh'

20. Conclusion / ks.ukh • The electric current flows from the (+) ve terminal to (-) ve terminal of the source through the circuit. • úoHq;a m%Njhl Odrdj .,k iïu; ÈYdj f,i i,lkqfha ^¬& isg ^-& w.%h olajd ÈYdjhs' Direction of the current flowing

21. Solar Cells / iQ¾h fldaI • The equipment used to generate electricity using light, is known as a solar panel. • wrist watches, calculators and various toys use solar energy • Solar cells are manufactured using elements like silicon. • wdf,dalh Ndú;fhka úÿ,sh W;amdokh i`oyd Ndú; lrk WmlrKh iQ¾h fldaIh f,i ye`Èkafõ' • iQ¾h fldaI Ndú;fhka l%shd lrk w;a Trf,daiq" .Kl hka;%" l%Svd NdKav we; • is,slka jeks uQ,øjH Ndú;fhka iQ¾h fldaI ksmojhs'

22. Studying the function of a solar panel iQ¾h iQ¾h fldaIhl fldaIhl l%shdldÍ;ajh l%shdldÍ;ajh y`ÿkd y`ÿkd . .ekSu ekSu • • • • • Connect the terminals of the electrical motor to the terminals of the solar panel. Expose the solar panel to light and observe. Change the terminals of the solar panel, which are connected to the motor. Observe whether the direction of turning of motor changes. Keep the solar panel in the dark and observe the running of motor • • • • iQ¾h fldaIfha w.%j,g úÿ,s fudagrfha w.% iïnkaO lrkak' wdf,dalh we;s ia:dkhl ;nd ksÍlaIKh lrkak' iQ¾h fldaIfha w.% udre lr fudagrhg iïnkaO lrkak' fudagrfha N%uK ÈYdj fjkia fõ oehs ksÍlaIKh lrkak fudagrh fjkqjg n,anh iïnkaO lr kej; l%shdldrlu isÿ lrkak' •

23. Observation / ksÍlaIKh Instance / wjia:dj wjia:dj Torch bulb / n,anh n,anh Electrical Motor / fudagrh fudagrh rotate / fudagrh N%uK fjs light up / oe,afjs When solar panel is exposed to light wdf,dalhg ;enQ úg not rotate / fudagrh N%uK fkd fjs Not blow / fkd oe,afjs When solar panel is kept in dark w`ÿre l< úg Not working / fudagrh N%uK fkd fjs Not blow / fkd oe,afjs When the terminals of solar panels are changed w.% udre l< úg

24. Conclusion / ks.ukh • Positive (+) and negative (-) terminals are marked on solar cells . • Therefore, the terminals should be connected correctly, when solar panels are used. • Electricity is generated in a solar panel, only when there is light • iQ¾h fldaIj,o (+& iy ^-& w.% igykaj we;' • fï ksid iQ¾h fldaI Ndú;fha § ksjerÈj w.% iïnkaO lsÍu l< hq;= h‘ • iQ¾h fldaIhlska úoHq;h W;amdokh jkqfha wdf,dalh we;s úg § muKs'

25. Solar panels / iQ¾h mek, • A single solar cell can generate a minute current. Therefore a large number of solar cells should be connected together to obtain a large electrical current. Such a connection is known as a solar panel. • tla iQ¾h fldaIhlska ksmojkqfha b;d l=vd Odrdjla neúka úYd, Odrdjla ,nd .ekSu i`oyd iQ¾h fldaI úYd, .Kkla tlg iïnkaO lr .; hq;= h' túg th iQ¾h iQ¾h mek,hl fõ' mek,hla f,i ye`Èka

26. Dynamo / vhskfudaj • Bicycle dynamo is used in most of the bicycles to light lamps at night. • Dynamo is another source, used to generate electricity • fndfyduhla mdmeÈj, ,dïmq oe,aùu i`oyd wjYH úÿ,sh ,nd.ekSug nhsisl,a vhskfudaj fhdod.kS' • vhskfudaj o úoHq;h ksmojd .ekSu i`oyd Ndú; lrk úoHq;a m%Njhls'

27. Various types of dynamos úúO úúO wdldrfha wdldrfha vhskfuda vhskfuda j¾. j¾. • various types of dynamos are used in fuel-driven electric generators, hydropower stations, thermal power stations and vehicles to generate electricity • bkaOk u.ska l%shdlrk úÿ,s ckl hka;%" úÿ,s n,d.dr" ;dm n,d.dr" r:jdyk wdÈfhys o úÿ,sh W;amdokh lrkqfha úúO wdldrfha vhskfuda u.sks'

28. Identifying how electricity is generated in a dynamo vhskfudajl úÿ,sh W;amdokh jk wdldrh y`ÿkd .ekSu • Wind the insulated copper wire around a cylindrical tube to make a coil. Clean both ends of the coil well and bconnect them to the galvanometer. Move one end of the bar magnet into and out of the coil. Observe how the indicator of the galvanometer moves. • • • • ng lene,a,la fyda úh<s fldaIhla jeks is,skavrdldr øjHhla jgd ;U lïìh T;d o`.rhla idod.kak' tys fofl<jr fyd`Èka iQrd msßisÿ lr .e,ajfkdaógrhg iïnkaO lrkak' oKav pqïnlh f.k ikakdhl o`.rh we;=<g yd bj;g p,kh lrkak .e,ajfkdaógrfha lgqj p,kh jk whqre ksÍlaIKh lrkak' • • •

29. Observation / ksÍlaIKh • The indicator of the galvanometer moves either two sides . • .e,ajfkdaógrfha lgqj fomig p,kh fjs Conclusion / ks.ukh • Generation of electricity in a conductor when magnetic field is cutting with the conductor • ikakdhlhla iu. pqïnl n, f¾Ld .eàfï § ikakdhlh ;=< úoHq;h W;amdokh fjs

30. Electromagnetic induction pqïnl pqïnl fm%arKh fm%arKh • Generation of electricity in a conductor when magnetic field is cutting with the conductor is known as electromagnetic induction. • ikakdhlhla iu. pqïnl n, f¾Ld .eàfï § ikakdhlh ;=< úoHq;h W;amdokh ùu úoHq;a pqïnl pqïnl fm%arKh fm%arKh f,i f,i ye¢ka ye¢ka fõ fõ' '

31. Bicycle dynamo / nhsisl,a nhsisl,a vhskfudaj vhskfudaj

32. • electricity is generated in the bicycle dynamo, according to the principle of electromagnetic induction. • nhsisl,a vhskfudaj ;=< úoHq;h ksmojkqfha o úoHq;a pqïnl fm%arK uQ, O¾uhg wkqj

33. Making a simple dynamo ir ir, , vhskfudajla vhskfudajla iE iE§ §u u

34. • The efficiency of the dynamo can be increased by increasing the number of turns of the coil and the power of the magnet. • o`.rfha o`.rfha fmdg fmdg ixLHdj ixLHdj iy pqïnlfha m%n,;dj m%n,;dj jeä jeä lsÍfuka lsÍfuka vhskfudafõ ld¾hlaIu;dj jeä l< yels h' pqïnlfha

35. Direct current and Alternating current ir, Odrdj yd m%;Hdj¾; Odrdj the dynamo is connected to the fan vibrates only (does not rotate). the small fan rotates when dry cells are connected vhskfudaj iïnkaO lr we;súg iq<x fm;a; lïmkh ùula muKla isÿfjs úh<s fldaI iïnkaOlr we;súg iq<x fm;a; N%uKh fjs

36. two LEDs illuminate alternately and the direction of the movement of milliammeter indicator changes constantly, when dynamo is connected and in rotating only one LED illuminates and the indicator of milliammeter deflects only in one direction in all instances when dry cells areconnected vhskfudaj lrleùfï § LED fol udrefjka udrejg oe,aùu yd ñ,s weógrfha lgqj p,kh jk ÈYdj jßka jr fjkia fjs úh<s fldaI iïnkaO lr we;s iEu úgu tla n,anhla muKla oe,aùu yd ñ,s weógrfha lgqj tla ÈYdjlg muKla .uka lrhs

37. Direct current and alternating current ir, Odrdj m%;Hdj¾; Odrdj Direct current Alternating current