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CHAPTER 8:ELECTROMAGNETISM

8.1 ELECTROMAGNETIS

1.The diagram shows 4 comp

placed on a horizontal cardstraight wire passes througcentre of the cardboard. Wcurrent is switched off, all tcompasses needles point n

(a) On the diagram beloarrows to show the dthe needles when theflows through the strinto the cardboard.

(b) Current passes throuPQ as shown below.circles represent thecompasses.

M

asses are

oard. Ah the

en thee

orth.

, drawirection ofcurrentight wire

gh a coilhe

(i) Draw arrows in thethe direction of the

(ii) The coils PQ act asState the magnetic p

P :

(iii)On the diagram belomagnetic field line ainside the coils PQ.direction of the mag

2.The structure of a relayrelated connections isdiagram below.

(i) What are the partshown in the diaX ___________

Y ___________

Z ___________

(ii) The relay coil ismetal core M. Stamaterial for this

(iii)Explain why thissuitable to be us

(iv)Give a reason whvoltage is switchrather than by inswitch directly involtage circuit.

ircle to showompass.

magnet.olarity at :

:

w, sketchround andShow the

netic field.

and itshown is

s X, Y and Zram?___________

___________

___________

ound on ate a suitable

etal core M.

material isd.

y the highd in this wayerting athe high

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3. Question 8: SBP 08Diagram 8.1 shows a simpleelectromagnet used for lifting andreleasing a small metal ball.

Diagram 8.1

(a) In Diagram 8.1, mark thedirection of the current flow inthe solenoid when the switch ison.

(b) (i) Name the magnetic pole atthe end of the core P whenthe switch is on?

.[ 1 mark ]

(ii) State the rule used todetermine the pole of themagnetic field.

[ 1 mark ]

(iii) Based on the solenoid inDiagram 8.1, draw themagnetic field lines that isform around the solenoidwhen the switch is on. Inyour diagram show thedirection of the magneticfield lines.

[ 2 marks ]

Material usedfor the core

Shape of thecore

Steel

Soft iron

Aluminium

Table 8

(c) Based on Table 8, state thesuitable properties to bechosen to built anelectromagnet and state thereason for your choice.

(i) Material used for theCore

..[ 1 mark ]

(ii) Reason

...........................................[ 1 mark ]

(iii) Shape of the core

...........................................[ 1 mark ]

(iv) Reason

...........................................[ 1 mark ]

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(d) The electromagnet inused in an electric belshown in Diagram 8.2.

Diagram 8.

Explain the workingof the electric bell.

8.2 MAGNETIC FORCE

4. Diagram below shows aarrangement to study thmagnetic field on a coppcarrying current. The brod is free to move aloncopper rails.

(c) isl as

rinciple

.

.

.

.[ 3 marks]

effect ofer rodre cooper

the bare

(a) On the diagram,with B the directimagnetic field.

(b) When the switchcopper rod movecopper rails. On

mark and labecurrent, I throcopper rod.

Mark and labedirection of ththe rod.

(c) Explain how thecopper rod is pro

______________

______________

______________

(d) What happen tothe copper rodyour answer wh

(i) the rheostatuntil its residecreases.

_____________

_____________

ark and labelon of the

is closed, thealong the

the diagram

l direction ofgh the

l, F , thee motion of

otion of theduced.

___________

___________

___________

he motion ofnd explain

en

is adjustedtance

___________

___________

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(ii) the battery is rea.c. power suppl

______________

______________

(e) Name one instrumeuse the principle in(b).

__________________

5. The diagram shows theof a direct current motor

(a) Name the part labele

(i) P : ____________

(ii) Q : ____________

(b) What is the functionlabeled(i) P : ____________

(ii) Q : ____________

(c) Label the direction ofcurrent in the coil.

(d) State and label the dithe forces acting on(i) the SV side of the

(ii) the TU side of the

laced byy

________

________

ts whicholved in

__________

tructure.

________

_______

f the part

________

________

the

rection of

coil: ____

coil: ____

(iii)name the ruledetermine thethe force.

____________

(e) What is the direc

rotation of the co

______________

6. The diagram showsarrangement of an ainvestigate the interbetween a current-cconductor and the

(a) Name the typeis used.

(b) When the switc(i) indicate a

direction

flows thr

(ii) what happewire X and gfor your ans

used todirection of

____________

ion of

il?

__________

thepparatus to

ctionrryingagnetic field.

f the magnet

is closed,nd label theof the current

ugh wire X.

to motion ofive the reasonwer.

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(ii)Explain how the pointerdeflects.

_________________________

_________________________

(iii) Why is the coil stops to

deflect?

__________________________

__________________________

9. Question 8:MRSM 08Diagram 8 shows a galvanometerwith a resistance of 5 and a full-scale deflection of 5 mA.

Diagram 8

The galvanometer uses theinteraction between the magneticfield of a permanent magnet and themagnetic field of an electromagnet tomeasure a small current. The coil ofthe galvanometer gets heated upquickly, thus affecting the readingshown by the pointer.

(a) What is meant byelectromagnet?

[1 mark]

Table 8 shows the specifications of fourgalvanometer J, K, L and M.

Galva-nometer

Wireusedfor thecoil

Corematerial

Numberof turnsof coils

J Thin Soft

iron

Large

K Thick Steel SmallL Thin Steel SmallM Thick Soft

ironLarge

(b) Based on Table 8, state thesuitable specifications for the coiland the core to make thegalvanometer more efficient.Give the reason for the suitability

of the aspects.(i) Wire used for the coil

...................................................

Reason

...................................................[2 marks]

(ii) Core material

...................................................

Reason

...................................................[2 marks]

(iii) Number of turns of the coil

...................................................

Reason

...................................................[2 marks]

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(c) Based on the answers idetermine the most suitgalvanometer in Tablemeasure a small curren

(d) A resistor is added to tgalvanometer to enableproduce a full-scale defwhen the current is 1 A(i) State how the resist

be connected to thegalvanometer. Tickcorrect answer.

In series with

galvanometer. Parallel to thegalvanometer.

(ii) Explain your answe

..................................

(iii) Calculate the resistthe added resistor.

10.Question 7:MRSM 09Diagram 7.1 shows a simplmotor.

Diagram 7.1

n 8(b),able

tot.

[1 mark]

eit to

lectionpere.

or should

(x) the

the

[1 mark]r in 8(d)(i)

................[1 mark]

nce of

[2 marks]

electric

(a) (i) Name the type oshown in the di

(ii) what is the fun

part labeled X?

(b) (i) By refering to Didraw the relatedin the diagram b

(ii) In your diagralabel the direcproduced.

(iii)State one factthe speed of rarmature.

(c) Diagram 7.2 showtype of electric moblender to grind foblade is attached tmotor.

f motorgram above.

.[1 mark]

tion of the

.[2 marks]

agram 7.1,catapult field

elow.[1 mark]

m, draw andtion of forces

[1 mark]

or that affectsotation of the

..[1 mark]

the sameor used in a

od where athe electric

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Diagram 7.2

Suggest and explain themodifications which need tfor each of the following:

(i) To enable the motor twith alternating curre

.....................................

.....................................

(ii) To increase the strenmagnetic field.

.....................................

.....................................

8.3 ELECTROMAGNETIINDUCTION

11.A straight thick copperconnected to a sensitive

zero galvanometer is movertically downwards inmagnetic field.

be done

o be usednt.

.................

................[2 marks]

gth of the

.................

.................[2 marks]

ire that iscentre-

veda

(a) Mark on the wireof the induced cuflows through it.

(b) Name the rule thwork out the direcurrent.

______________

(c) Describe the effeinduced current i(i) the wire is mo

upwards at a l

____________

(ii) the wire is moupwards at a

____________

(iii)The wire is hein between thmagnet.

____________

12.The south pole of amoved towards a soconnected to a senszero galvanometer.

the directionrrent that

t is used toction of the

___________

ct on thef:ved verticallyow speed,

____________

ved verticallyigher speed.

___________

ld stationarypoles of the

____________

ar magnet islenoid that ititive centre-

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i. Mark on the solenoid:(i) the end that will become

a south pole.

(ii) The direction of theinduced current.

ii. State three ways to increasethe induced current in thesolenoid

________________________

________________________

13.Question 2:Melaka 09Diagram 2.1 shows a bar magnet

before and when is pushed into asolenoid.

Diagram 2.1

(a) Name the science phenomenoninvolved in Diagram 2.1?

..[1 mark]

(b) State the polarity of the solenoid

at mark X. Tick () the correctanswer in the box below.

North

South[1 mark]

(c) Diagram 2.2 shows a magnet baris pulling away from inside a

solenoid.

Diagram 2.1

On Diagram 2.2(i) mark the direction of the

current flow in the circuit

(ii) by using an arrow mark thecompass direction on thecompass above

[2 marks]

14.Question 4Diagram 4 shows a bar magnet ishung on a spring that attached to aretort stand. The bar magnet isdisplaced downwards and releasedso it can oscillate through a solenoidwhich is connected to a centre-zerogalvanometer.

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(a) What is meant byelectromagnetic induct

..................................

(b). When the bar magnettowards the solenoid, tgalvanometer pointera while.

(i) Explain why thegalvanometer pointdeflects?

..................................

(ii). State the polarity ofand end B of the so

A : ..........................

B : ..........................

(c) If the spring is replacestiffer spring,(i)state the change to t

of deflection of thegalvanometer pointer

.....................................[

ion?

.................

[1 mark]

oveheeflect for

r

................[1 mark]

end Alenoid.

.............

.................2 marks]

by a

e angle

?

.................1 mark]

(ii) Give the reasonanswer.

............................

15.Question 6:SBP 07Diagram 6.1 and 6.2 shmagnet is pushed intospeed of 2 ms-1.

(a) State the physical qrepresented by thethe galvanometer.

(b) Based on Diagram

Diagram 6.2:(i) State two differebe observed froand Diagram 6.2

............................

............................

for your

.......................[1 mark]

w a barsolenoid at a

uantity that isdeflection of

.......[1 mark]

.1 and

nces that canDiagram 6.1

.

........................

........................

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(ii) Based on the answeexplain why these dioccur?

...................................

...................................

...................................

(c) Name the physicsinvolved in 6(b)(ii)

...............................

(d) Explain why the directicurrent in the solenoidas shown in Diagram 6Diagram 6.2?

.......................................

.......................................

16.Kedah 07 Q6Diagram 6.1 and Diagram 6that a current is induced insolenoid when there is relatmotion between the solenoibar magnet.

Diagram 6.1 Di

(a) What is meant by indcurrent?

....................................

[2 marks]

r in (b)(i),fferences

.................

.................

.................[2 marks]

law.

.................[1 mark]

on ofis upward

.1 and

.................

.................[2 marks]

.2 showaived and the

agram 6.2

uced

.................

(b) Based on the directicurrent in Diagram 6Diagram 6.2;

(i) Label the polariteach solenoid inY.

(ii) Label the directiothe bar magnet iand Diagram 6.2

[2 marks]

(c)(i) Based on the ans

and 6(b)(ii), statethe polarity at thsolenoid on thebar magnet.

..............................

.............................

(ii) Name the law th

(c)(i).

............................

(d) Suggest one methothe induced currentsolenoid.

...................................

[1 mark]

on of the.1 and

at the end ofbox X and box

[2 marks]

n of motion ofDiagam 6.1

wers in 6(b)(i)

the effect ofend of theotion of the

........................

........................[2 marks]

t applies to

........................[1 mark]

to increasein the

........................

[1 mark]

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17.The diagram shows the structuraldesign of a generator.

(a) Name the principle used inthe generator.

_______________________

(b) Mark the directions of currentflow in WX and YZ when theside WX of the coil isdisplaced in downwards

direction.

(c) Draw a graph to show thevariation with time of thecurrent in conductor YZ.

(d) What happens to the currentflows in conductor YZ whenthe speed of the coilsrotations is increased?

_______________________

8.4 TRANSFORMER

18.Question 3:Negeri 9 09The diagram 3 shows a U-shaped

laminated soft iron core is woundwith insulated copper wire AB andCD. An a.c. voltage of 240 V isconnected at the end of AB and abulb 12V 60W is connected at the endCD.

(a) What type of transformer isshown in Diagram 3.

..

[ 1 mark ]

(b) State one reason why the a.c.voltage is supplied.

[ 1 mark ]

(c) The bulb lights up with normalbrightness. Determine the ratio ofthe number of turns in the coil AB

to the number of turns in the coilCD.

[ 2 marks ]

(d) The voltage supply 240 V.

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alternating current. is ra voltage supply 240 Vcurrent.

(i) What happens to brithe bulb.

(ii) Give the reason for yanswer.

19.Question 4: Johor 2007

Diagram 4.1 shows a simpltransformer used to light ulabelled 24 V, 36 W.

When the mainsswitched on, thevery dim.

(a) State two ways in whicbrightness of the bulbincreased without chanvoltage of the mains su

.........................................

........................................

(b) Explain why the core isfrom iron.

placed bydirect

htness of

[1 mark ]ur

...[ 1 mark ]

a bulb

upply isulb is

thean be

ging thepply.

..................

..................[2 marks]

made

.................................

(c) For the bulb operatinormal brightness,

(i) the current in thcoil.

(ii) the current in the prAssume that the traideal.

20.Question 6: Teknik 0Table 6 gives the detailtransformers P and Q

TABLE 6

(a) Compare the nu

for each transfor

.............................

(b) Compare the volttransformers.

.............................

.........................[1 mark]

ng at thecalculate:

secondary

[2 marks]

imary coil.nsformer is

[2 marks]

7of two

ber of turns

mers.

........................[1 mark ]

ages for each

........................

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[1 mark]

(c) (i) State the relationship betweenthe number of turns of the coiland the voltages for both

transformers.

.....................................................

.....................................................[1 mark]

(ii) Therefore,determine the typeof transformer P and Q.

Transformer P : .

Transformer Q : ..[2 marks]

(c) (i) Name the type of electriccurrents that a transformercan change .

....................................................[1 mark]

(ii) What happens if another type

of current applied to theprimary coil? Explain youranswer

[2 marks]

ESSAY QUESTIONS

21.Conceptual: Perak 07Diagram 10.1 and 10.2 show

insulated copper wires are wrappedaround rods to form solenoids. Thesolenoids are connected toammeters, rheostats, switches anddry cells.

Diagram 10.1

Diagram 10.2

When the switch is on and paper

clips of the same amount are put inthe plates, the paper clips areattracted to the solenoids.(a) What is an electromagnet?

[1 mark](b) Using Diagram 10.1 and Diagram

10.2, compare the number ofturns in solenoid, the magnitudeof current flowing and thenumber of paper clips attractedto the solenoid.

[3 marks](c) State the relationship between

the strength of the magneticfield and(i) the magnitude of current(ii) the number of turns in

solenoid[2 marks]

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22.Conceptual: MRM 07Figure 10.1 shows a magneon a stationary trolley. Figis the situation when the trstationary while Figure 10.1situation when the trolley isinto the solenoid. Figure 1

shows a conductor which istationary in the magnetic ffigure 10.2(b) shows the cobeing moved downwards inmagnetic field.

(a) (i) What is meant by mfield?

(ii) Observe Figure 10.10.2, compare the galreadings when there irelative motion betwemagnet and the condwhen there is relativebetween them. Relate

current and the relativbetween the conductomagnetic field to deduphysic concept. Namphysics concept thatthe above situation.

placedre 10.1(a)lley is(b) is themoving.2(a)

ield whileductorthe

agnetic

[1 mark]

1 andanometer

non thector and

motionthe

e motionr and thece a

thexplains

[5 marks]

23.Understanding : PerDiagram 10.3 shows a selectromagnet consistswith soft iron core insidmagnet bars are hung fsides of the solenoids.

Diagr

Explain what happens tand magnet Q when th

24.Understanding: MRCompare the structurescurrent and changes inbetween a direct currenand an alternating curr

25.Understanding: SBPDiagram 12.1 shows twtransformers P and Q.

(i) What is meant by a

ak 07impleof a solenoide. And, two

reely at both

m 10.3

o magnet Pswitch is on.

[4 marks]

M 07, direction ofenergy formst generatornt generator.

[4 marks]

07

transformer?[1 mark]

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(ii) Based on Diagram 12.1, whichtransformer is a step-uptransformer? Give one reason foryour choice.

[ 2 marks]

(iii)Practically a transformer is not

100% efficient. Some energy islost in the transformer. List thefactors that cause the energyloss in a transformer.

[3 marks]

26.Qualitative problem: Perak 07Diagram 10.4 shows an electric bellconnected to dry cells.

Diagram 10.4

(i) Explain how the electric bellfunctions.

[4 marks]

(ii) Explain the modificationthat needs to be done on

the electric bell to enable itto ring louder.[6 marks]

27.Qualitative problem: MRSM 07You are given two coils R and S, with50 and 100 turns respectively, an ironcore and a 240 V a.c power supply.All the materials are used to build asimple transformer.

(i) Using all the materials supplied

and with the aid of a labeleddiagram, explain how you aregoing to build a simple step-uptransformer.

[4 marks]

(ii) Suggest modifications that needto be done to the transformer toincrease its efficiency.

[6 marks]

28.Making decision: Teknik 07Table 12.1 shows the voltagegenerated and the type of currentproduced by four power supplystations.

TABLE 12.1

(i) State which power supply stationis suitable for the long distancetransmission of electricity.Justify your choice.

[ 3 marks ]

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(iii) Table 12.2 shows thecharacteristics of fourcables that are of the slength.

Cable Diameter/cm

Densit/kgm-3

X 3 7 280Y 2 5 200Z 6 2 000

You are asked to choosthe cables to be used inNational Grid Network. Esuitability of each of thecharacteristics of the caChoose the most suitabl

and justify your choice.[

29.Making decision: SBP 0The transmission of electrithe National Grid Network uvoltage cables. You are assstudy the characteristics ofwhich could be used as tracable. Table 12 shows the

characteristics of four transcables.

Cable Resistivitym

-1DensityKgm-3

Cost

P 3.0 x 10-7 5 x 105 lowQ 1.8 x 10-8 2 x 103 lowR 7.5 x 10-7 8 x 102 highS 7.0 x 10-8 4 x 103 medium

Based on the table 1(i) Explain the suitabi

characteristics ofto be used as trancable.

(ii) Determine the motransmission cabl

ypes ofame

Rate ofexpan-

sionLowHighlow

one ofthexplain the

les.e cable

marks ]

ity overses highigned tocablessmission

mission

Rate ofthermalexpansionhighlowmediumhigh

;lity of thethe cablessmission

t suitableto be

used and giveyour choice.

30.Quantitative probleDiagram 12.1 shows tw

transformers P and Q.

Calculate the output vo(i) transformer P(ii) (ii) transforme

31.Quantitative problePower of 15 kW is transsmall generator to a ruralong 5000 m of cablestotal resistance of 3 .transmitted at the usualvoltage of 240 V. Calcul

(i) The current in the c(ii) The power loss due

of the cables(iii) The percentage of lo

reasons for

[10 marks]

: SBP 07

tage of

r Q

[ 4 marks ]

:mitted from aal schoolthat have ahe power ismains supply

ate;

blesto the heating

ss of power[5 marks]

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32.Section C:Trengganu 07Diagram 12.1 shows an ele

Diagram 1

(a) (i) State the energytransformation thatplace when an elecrings.

(b) An electric bell is able ta louder sound .Table 12 shows the

characteristics of electP,Q,R,S and T which cproduce a loud sound.

Electricbell

Size ofthehammer

Distancebetweenthehammerandgong/cm

Thenumofturnof thcoilarousoft

ironcore

Q Big 5.0 100R Big 5.0 100S Small 5.0 50T Small 2.0 100

tric bell.

2.1

takestric bell

[1 mark]

o produce

ric bellsuld

ber

se

nd

Curva-ture ofthegong

HighLowLowLow

You are asked to studybells P,Q,R,S and T.Explain the suitability ocharacteristic of the eleTable 12 and hence, detelectric bell is able to ploudest sound.

Justify your choice.

(c) Diagram 12.2 shobell 12 V,10 W is coutput of a transfefficiency of the tr80%.

Calculate(i) the electric cur

electric bell(ii) the electric curr

primary coil

33.Section B: KelantanDiagram 10.1 and Diagra copper wire carryingplaced in a permanentThe magnetic field prodcatapult field.

the electric

f eachctric bell inermine whichroduce the

[10 marks]

s an electricnnected to thermer Thensformer is

rent in the

ent in the

[5 marks]

08am 10.2 show

urrent isagnetic field.

uced is called

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(a) What is meant by cata

(b) Using Diagram 10.1 an10.2, compare the nummagnet used, the angldeflection of the coope

the angle of deflectionammeter indicator.

(c) State the relationship bthe strength of the cataproduced and(i) number of magnet u

(ii) angle of deflection owire

[2

(d) Diagram 10.3 shows a sused to study the effectmagnetic field of a currcarrying copper rod

(i) Explain what happecopper rod when this turned on

(ii) The dry cells are rewith 12 V a.c. Explaihappens to copperthe switch is turned

ult field ?[1 mark]

Diagramber of

ofr wire and

of

[3 marks]

tweenult field

sed

f copper

marks]

et ups ofnt-

ns to theswitch

[2 marks]

lacedn whatod whenon.2 marks]

(e) Diagram 10.4 showelectric motor .

Diagram 1

(i) Explain how therotate.

(ii) Suggest three mothat need to be do

electric motor to iefficiency of theexplanation for eagiven.

a d.c.

.4

otor is able to

[4 marks]

dificationsne on the d.c

crease theotor. Give an

ch suggestion

[6 marks]

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34.Section C: Kedah 08Diagram 12.1 shows a simpcurrent electric motor.

(a) What is meant by dircurrent?

(b) Using the conceptof t

magnetic effect of ancurrent, explain withdiagrams how forcesproduced on a wire ias shown in Diagram

(c) Diagram 12.2 shows tfeatures in the desigdirect current motorsand S. You are requi

determine the most smotor to lift a heavysmoothly. Study theof all the four motors- The density of the

the coil- The number of tur

coil.- The strength of th- The number of se

the commutator

Explain the suitabfeatures. Justifychoice.

le direct

ct

[1 mark]

he

electriche aid ofarethe coil,

12.1.[4 marks]

heof four

, P, Q, Red to

uitablebject

features

wires of

ns of the

magnetments in

ility of theour

Model

Densityofthe

coil

Numberof

turnsofthecoi

l

Strengthof

magnet

P 9200 4000 Low

Q 11600 9000 High

R 8960 8000 High

S 10500 5000 Med-ium

[10 marks]

(d) A 12 W electric mload of 3.0 N throof 8.0 m in 5.0 s.(i) the work d

motor in lif(ii) the usefulof the mot

(iii) the efficienmotor

Numberof

segmentsin

thecommutator

2 segments

4 segments

8 segments

8 segments

otor lifts augh a height

alculate,ne by the

ting the load,utput powerrcy of the

[5 marks]

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35.Melaka 08 section BDiagram 9.1 shows the pattmagnetic field formed whenflows in a coil. The magnetstrength is greater at the cecompared to the edge

(a) (i) What is meant by mfield?

(ii) Explain why the strthe magnetic field iat the center

(b) Diagram 9.2 and Diagrshow the the magneticproduce when currentflows in a conductor.Diagram 9.4 shows thefield produced when ccarrying conductors inDiagram 9.2 and Diagrplaced in magnetic fiel

rn ofcurrent

ic fieldnter

agnetic

[1 mark]

ength ofgreater

[3 marks]

m 9.3field

magneticrrent

m 9.3 isd

(i) Based on DiagramDiagram 9.3, comp

- pattern of the m- direction of the

(ii) Based on Diagram9.3 and 9.4 comparof the magnetic fiel

(iii) Based on Diagram

the direction of theforces

(iv) Name one instrumeuses the same prinDiagram 9.4. Explaisimilarities.

(c) Diagram 9.5 showcoil loudspeaker.

.2 andare theagnetic fieldmagnetic field9.2 ,Diagram

the pattern

.4 compare

resultance

nt whichiple as in

n the

[5 mark]s a moving

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FIZIKMOZAC 2010

You are required to give sosuggestions to design a moloudspeaker which is functican produce loud sound.Using the knowledge onelectromagnet, forces and tproperties of materials, expsuggestions based on the faspects ;(i) the shape of the mag

(ii) the position of the co(iii) material used for the(iv) type of electrical sup(v) material used for the

the loudspeaker[10 ma

evingonal and

helain the

llowing

net

ilconely

body of

rks]

36.Section B:SBP 08(a) Diagram 10.1 and D

show the relativebetween the magnesolenoid. Ends of tconnected to a centgalvanometer.

Diagram 10

Diagram 1

Using Diagram 10.1

10.2, compare:(i) the direction of t

of the magnet(ii) the deflection of t

galvanometer poi(iii) Relate the movem

magnet, the polariof the coil and thethe magnet to dedphysics law.

(b) Name the phydescribes the oDiagram 10.110.2.

iagram 10.2otion

t ande coils arere-reading

.1

.2

and Diagram

he movement

eter

ent of thety at the topforce acts on

uce a relevant

[5 marks]

ics law thatservations in

and Diagram

[1 mark]

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FIZIKMOZAC 2010

(a) What is meant by cata

(b) Using Diagram 10.1 aDiagram 10.2, comparangle of deflection of

ammeter pointer , thesupply and the distanby the copper rods.

[

(c) State the relationshipthe strength of the forcon the copper rods an

(i) the moving distanccopper rods,

(ii) the size of electric

[

(d) Diagram 10.3 shows tcopper strips, WX andconnected to a circuit.

pult field?[ 1 mark]

dthe

he

powere moved

3 marks]

etweene exerted

of the

urrent,

2 marks]

o thinYZ,

Explain what hapcopper strip WXthe switch is clos

(e) Diagram 10.4 showsammeter

Explain how you woulmoving coil ammeter thfunction better. In youremphasize the followin

(i) the sensitivity of th

(ii) the shape of the pemagnet,

(iii) the shape of the co

(iv) the type of the core

(v) the type of the amm

[ 10 marks]

pens tond YZ when

ed.[ 4 marks]

a moving coil

design aat canexplanation,aspects:

ammeter,

manent

e,

material,

eter scale.

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FIZIKMOZAC 2010

38.Section B:Kelantan 09Diagram 10.1 and Diagramthe deflection of a galvanowhen a bar magnet are pustwo identical solenoids.

(a) What is meant byelectromagnetic indu

(b) Using Diagram 10.1 aDiagram 10.2,

(i) State the magnetiend P when the bmagnets are pushthe solenoids.

(ii) Compare the numbar magnets and tdeflection of thegalvanometer.

(c) State the relationship(i) The number of

magnets and t

0.2 showetered into

ction?nd

pole atr

ed into

[1 mark]

ber of thehe

[2 marks]between

bare

strength offield

(ii) The strengmagnetic fideflectiongalvanome

(d) Diagram 10.3 shotransformer.

(i) Name the type o

(ii) Explain how theinduced in the s

(e) Diagram 10.4 showgenerator.

the magnetic

[1 mark]th of theled and thef the

ter

[1 mark]

ws an ideal

f transformer.[1 mark]

current iscondary coil.

[3 marks]

an a.c

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FIZIKMOZAC 2010

Suggest modifications that can bemade to increase the output currentto the generator in Diagram 10.4.State and modifications based on thefollowing aspects:

(i) Strength of the magnet(ii) Shape of the magnet

(iii) Number of turns of the coil(iv) Diameter of the wire of the

coil(v) The speed of rotation

[10 marks]

39.Section B:Pahang 09The National Grid Network is animportant system that ensures the

electrical power is suppliedcontinuously. After the generation ofelectricity at the power station,electricity is transferred via a numberof substations and transformersbefore the electricity reaches theconsumer.

Table 10.1 shows current andpotential difference before and afterpassing through substations B

during reception of electricity bycustomers.

Physicalquantity

Transmission ofelectricity

Beforesubstation

A

Aftersubstation

ACurrent 80 A 15 A

Potential

Difference

25 kV 132 kV

Table 10.1

Table 10.2 shows current andpotential difference before and afterpassing through substations B

during reception of electricity bycustomers.

Physicalquantity

Transmission ofelectricity

Before

substationB

After

substationB

Current 15 A 60 A

PotentialDifference

132 kW 33 kW

Table 10.2

(a) (i) What is meant by potentialdifference?

[1 mark]

(ii) Using only information in Table10.1 and 10.2, comparecharacteristic of electricalpower transmitted andreceived by customers. Statethe relationship betweencurrent and potentialdifference during transmissionand reception of electricalpower.

[5 marks]

(b) Generation of electrical powerinvolves the use of renewableresources and unrenewableresources. With the use ofsuitable examples, comparethe two types of resources.

[4 marks]

(c) During transmission and

reception of electrical power,pylons such as shown inDiagram 10.1 play an importantrole.

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FIZIKMOZAC 2010

Based on Diagram 10your knowledge abotransmission of electpower and other relatphysics concepts, ex(i) The characteri

materials used

the pylons.(ii) The design of tpylons.

(iii) The characterithe cable usedelectrical powetransmmission

40. Section B:SBP 09(a) Diagram 10.1 and Diagrashows two identical electroand Y .

Diagram 10.1 Dia

(i) What is meant byelectromagnet?

.1 andt

ricaledplaintics ofto build

he

tics ofin ther

[10 marks]

m 10.2magnet, X

gram 10.2

[ 1 mark ]

(ii) Using Diagram 10.10.2 compare thethe amount of ironthe magnetic fieldthe two electrodes.current flow and afiling attracted by t

electromagnet andfield strength.

(b) Diagram 10.3 shobreaker.

Diagr

Explain how the circ

works.[ 4 mar

and Diagramurrent flow,

filing andtrength ofRelate theount of iron

he

the magnetic

[ 5 marks ]

s a circuit

m 10.3

uit breaker

ks]

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(c) Diagram 10.4 shows an a.cgenerator

Diagram10.4

(i) Explain how the generator

works to produce alternatingcurrent.[ 4 marks ]

(ii) Explain the modification thatneeds to be done on thegenerator and the externalcircuit to enable thegenerator to be a d.cgenerator and produce morecurrent.

[6 marks]