FIZIKMOZAC 2010

CHAPTER 8:ELECTROMAGNETISM

8.1 ELECTROMAGNETISM

1.The diagram shows 4 compasses areplaced on a horizontal cardboard. Astraight wire passes through thecentre of the cardboard. When thecurrent is switched off, all thecompasses needles point north.

(a) On the diagram below, drawarrows to show the direction ofthe needles when the currentflows through the straight wireinto the cardboard.

(b) Current passes through a coilPQ as shown below. Thecircles represent thecompasses.

ELECTROMAGNETISM

The diagram shows 4 compasses areplaced on a horizontal cardboard. Astraight wire passes through thecentre of the cardboard. When thecurrent is switched off, all thecompasses needles point north.

On the diagram below, drawarrows to show the direction ofthe needles when the currentflows through the straight wire

Current passes through a coilPQ as shown below. Thecircles represent the

(i) Draw arrows in the circlthe direction of the compass.

(ii) The coils PQ act as a magnet.State the magnetic polarity at :

P : Q :

(iii)On the diagram below, sketchmagnetic field line around andinside the coils PQ. Show thedirection of the magneti

2.The structure of a relay and itsrelated connections is shown isdiagram below.

(i) What are the parts X, Y and Zshown in the diagram?X _______________________Y _______________________Z _______________________

(ii) The relay coil is woundmetal core M. State a suitablematerial for this metal core M.

(iii)Explain why this material issuitable to be used.

(iv)Give a reason why the highvoltage is switched in this wayrather than by inserting aswitch directly in the highvoltage circuit.

Draw arrows in the circle to showthe direction of the compass.The coils PQ act as a magnet.State the magnetic polarity at :

P : Q :

On the diagram below, sketchmagnetic field line around andinside the coils PQ. Show thedirection of the magnetic field.

The structure of a relay and itsrelated connections is shown is

What are the parts X, Y and Zshown in the diagram?

_____________________________________________________________________

The relay coil is wound on ametal core M. State a suitablematerial for this metal core M.

Explain why this material issuitable to be used.

why the highvoltage is switched in this wayrather than by inserting aswitch directly in the 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 in 8 (c) isused in an electric bell asshown in Diagram 8.2.

Diagram 8.2

Explain the working principleof the electric bell.

.

.

.

.

8.2 MAGNETIC FORCE

4. Diagram below shows anarrangement to study the effect ofmagnetic field on a copper rodcarrying current. The bare cooperrod is free to move along the barecopper rails.

The electromagnet in 8 (c) isused in an electric bell asshown in Diagram 8.2.

Diagram 8.2

Explain the working principle

.

.

.

.[ 3 marks]

Diagram below shows anarrangement to study the effect ofmagnetic field on a copper rodcarrying current. The bare cooperrod is free to move along the bare

(a) On the diagram, mark and labelwith B the direction of themagnetic field.

(b) When the switch is closed, thecopper rod move along thecopper rails. On the diagram mark and label direction of

current, I through thecopper rod.

Mark and label, F , thedirection of thethe rod.

(c) Explain how the motion of thecopper rod is produced.

______________________________________________________________________________

(d) What happen to the motion ofthe copper rod and explainyour answer when(i) the rheostat is adju

until its resistancedecreases.

_________________________

_________________________

ram, mark and labelwith B the direction of the

When the switch is closed, thecopper rod move along thecopper rails. On the diagram

mark and label direction ofcurrent, I through the

Mark and label, F , thedirection of the motion of

Explain how the motion of thecopper rod is produced.

____________________________________________________

______________

What happen to the motion ofthe copper rod and explainyour answer when

the rheostat is adjusteduntil its resistance

_________________________

_________________________

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(ii) the battery is replaced bya.c. power supply

_______________________

_______________________

(e) Name one instruments whichuse the principle involved in(b).

____________________________

5. The diagram shows the structureof a direct current motor.

(a) Name the part labeled

(i) P : _____________________

(ii) Q : ____________________

(b) What is the function of the partlabeled(i) P : _____________________

(ii) Q : _____________________

(c) Label the direction of thecurrent in the coil.

(d) State and label the direction ofthe forces acting on(i) the SV side of the coil: ____

(ii) the TU side of the coil: ____

the battery is replaced bya.c. power supply

_______________________

_______________________

instruments whichse the principle involved in

__________________________

The diagram shows the structureof a direct current motor.

Name the part labeled

P : _____________________

Q : ____________________

What is the function of the part

P : _____________________

Q : _____________________

Label the direction of the

State and label the direction of

e SV side of the coil: ____

e TU side of the coil: ____

(iii)name the rule used todetermine the direction ofthe force.

________________________

(e) What is the direction ofrotation of the coil?

_________________________

6. The diagram shows thearrangement of an apparatus toinvestigate the interactionbetween a current-carryingconductor and the magnetic field.

(a) Name the type of the magnetis used.

(b) When the switch is closed,(i) indicate and label the

direction of the currentflows through wire X.

(ii) what happen to motion ofwire X and give the reasonfor your answer.

name the rule used tothe direction of

________________________

What is the direction ofrotation of the coil?

_________________________

The diagram shows thearrangement of an apparatus toinvestigate the interaction

carryinge magnetic field.

Name the type of the magnet

When the switch is closed,indicate and label thedirection of the currentflows through wire X.

what happen to motion ofwire X and give the reasonfor your answer.

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(c) Suggest two ways to changethe direction of the motion ofwire X.

_______________________

_______________________

7. Question 5:Pahang 08Diagram 5 demonstrates the forceacting on a current carryingconductor in a magnetic field.

Diagram 5

(a) When the switch is closed, whatobservation can you make?

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

(b) State the rule which can be usedto determine the direction ofmotion of the copper wire?

(c) (i) If the direction of current isreversed, what differentobservation can be made?

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

(ii) Draw the pattern ofelectromagnetic field thatproduces the motion of thecopper wire as in (a)?

to changethe direction of the motion of

_______________________

_______________________

Diagram 5 demonstrates the forceacting on a current carryingconductor in a magnetic field.

witch is closed, whatobservation can you make?

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

State the rule which can be usedto determine the direction ofmotion of the copper wire?

[1 mark]

of current isreversed, what differentobservation can be made?

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

electromagnetic field thatproduces the motion of thecopper wire as in (a)?

(iii) How can the magnitude of theforce be increased?

.

.

8. Figure(a) shows the structuraldesign of a moving coil ammeter.

Figure(a)

(a) On Figure(b) draw the pattern ofthe magnetic fields formedbefore the current flows throughthe coil.

Figure(b)

(b) When the current flows throughthe coil, the pointer isdeflected.(i) What type of current is used?

n the magnitude of theforce be increased?

.

.[2 marks]

Figure(a) shows the structuraldesign of a moving coil ammeter.

Figure(a)

On Figure(b) draw the pattern ofthe magnetic fields formedbefore the current flows through

Figure(b)

When the current flows throughthe coil, the pointer is

What type of current is used?

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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 by

electromagnet?

[1 mark]

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

Wireusedfor thecoil

Corematerial

Numberof turnsof coils

J Thin Softiron

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 suitabilityof 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]

FIZIKMOZAC 2010

(c) Based on the answers in 8(b),determine the most suitablegalvanometer in Table 8 tomeasure a small current.

(d) A resistor is added to thegalvanometer to enable it toproduce a full-scale deflectionwhen the current is 1 Ampere.(i) State how the resistor should

be connected to thegalvanometer. Tick (x) thecorrect answer.

In series with thegalvanometer. Parallel to thegalvanometer.

(ii) Explain your answer in 8(d)(i)

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

(iii) Calculate the resistance ofthe added resistor.

10.Question 7:MRSM 09Diagram 7.1 shows a simple electricmotor.

Diagram 7.1

Based on the answers in 8(b),determine the most suitablegalvanometer in Table 8 tomeasure a small current.

[1 mark]

A resistor is added to thegalvanometer to enable it to

scale deflectionwhen the current is 1 Ampere.

State how the resistor shouldbe connected to thegalvanometer. Tick (x) the

series with the

. Parallel to the

[1 mark]Explain your answer in 8(d)(i)

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

istance of

[2 marks]

Diagram 7.1 shows a simple electric

(a) (i) Name the type of motorshown in the diagram above.

.

(ii) what is the function of thepart labeled X?

.

(b) (i) By refering to Diagram 7.1,draw the related catapult fieldin the diagram below.

(ii) In your diagram, draw andlabel the direction of forcesproduced.

(iii)State one factor that affectsthe speed of rotation of thearmature.

..

(c) Diagram 7.2 shows the sametype of electric motor used in ablender to grind food where ablade is attached to the electricmotor.

(i) Name the type of motorshown in the diagram above.

.[1 mark]

what is the function of the

.[2 marks]

(i) By refering to Diagram 7.1,draw the related catapult fieldin the diagram below.

[1 mark]

In your diagram, draw andlabel the direction of forces

[1 mark]

State one factor that affectsof rotation of the

..[1 mark]

Diagram 7.2 shows the sametype of electric motor used in ablender to grind food where ablade is attached to the electric

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Diagram 7.2

Suggest and explain themodifications which need to bfor each of the following:

(i) To enable the motor to be usedwith alternating current.

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

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

(ii) To increase the strength of themagnetic field.

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

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

8.3 ELECTROMAGNETI CINDUCTION

11.A straight thick copper wire that isconnected to a sensitive centrezero galvanometer is movedvertically downwards in amagnetic field.

modifications which need to be done

To enable the motor to be usedwith alternating current.

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

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

To increase the strength of the

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

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

ELECTROMAGNETI C

A straight thick copper wire that isconnected to a sensitive centre-zero galvanometer is moved

tically downwards in a

(a) Mark on the wire the directionof the induced current thatflows through it.

(b) Name the rule that is used towork out the direction of thecurrent.

__________________________

(c) Describe the effect on theinduced current if:(i) the wire is moved vertically

upwards at a low speed,

________________________

(ii) the wire is moved verticallyupwards at a higher speed.

_______________________

(iii)The wire is held stationaryin between the poles of themagnet.

_____________________

12.The south pole of a bar magnet ismoved towards a solenoid that itconnected to a sensitive centrezero galvanometer.

Mark on the wire the directionof the induced current that

Name the rule that is used towork out the direction of the

__________________________

Describe the effect on theent if:

the wire is moved verticallyupwards at a low speed,

________________________

the wire is moved verticallyupwards at a higher speed.

_______________________

The wire is held stationaryin between the poles of the

________________________

The south pole of a bar magnet ismoved towards a solenoid that itconnected to a sensitive 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 magnetbefore 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 solenoidat 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 asolenoid.

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 induction?

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

(b). When the bar magnet movetowards the solenoid, thegalvanometer pointer deflect fora while.

(i) Explain why thegalvanometer pointerdeflects?

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

(ii). State the polarity of end Aand end B of the solenoid.

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

B : ...........................................[2 marks]

(c) If the spring is replaced by astiffer spring,(i)state the change to the angle

of deflection of thegalvanometer pointer?

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

electromagnetic induction?

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

When the bar magnet movetowards the solenoid, thegalvanometer pointer deflect for

galvanometer pointer

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

State the polarity of end Aand end B of the solenoid.

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

B : ...........................................[2 marks]

(c) If the spring is replaced by a

state the change to the angle

galvanometer pointer?

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

(ii) Give the reason for youranswer.

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

15.Question 6:SBP 07Diagram 6.1 and 6.2 show a barmagnet is pushed into a solespeed of 2 ms-1.

(a) State the physical quantity that isrepresented by the deflection ofthe galvanometer.

.......

(b) Based on Diagram 6.1 andDiagram 6.2:(i) State two differences that can

be observed from Diagram 6.1and Diagram 6.2.

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

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

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

(ii) Give the reason for your

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

Diagram 6.1 and 6.2 show a barmagnet is pushed into a solenoid at a

State the physical quantity that isrepresented by the deflection of

.......[1 mark]

Based on Diagram 6.1 and

State two differences that canbe observed from Diagram 6.1

Diagram 6.2.

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

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

FIZIKMOZAC 2010

(ii) Based on the answer in (b)(i),explain why these differencesoccur?

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

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

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

(c) Name the physics lawinvolved in 6(b)(ii).

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

(d) Explain why the direction ofcurrent in the solenoid is upwardas shown in Diagram 6.1 andDiagram 6.2?

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

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

16.Kedah 07 Q6Diagram 6.1 and Diagram 6.2 showthat a current is induced in asolenoid when there is relativemotion between the solenoid and thebar magnet.

Diagram 6.1 Diagram 6.2

(a) What is meant by inducedcurrent?

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

[2 marks]

Based on the answer in (b)(i),explain why these differences

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

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

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

Name the physics lawinvolved in 6(b)(ii).

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

Explain why the direction ofcurrent in the solenoid is upwardas shown in Diagram 6.1 and

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

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

Diagram 6.1 and Diagram 6.2 showthat a current is induced in asolenoid when there is relativemotion between the solenoid and the

Diagram 6.1 Diagram 6.2

What is meant by induced

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

(b) Based on the direction of thecurrent in Diagram 6.1 andDiagram 6.2;(i) Label the polarity at the end of

each solenoid in box X and boxY.

(ii) Label the direction of motion ofthe bar magnet in Diagam 6.1and Diagram 6.2

[2 marks]

(c)(i) Based on the answers in 6(b)(i)and 6(b)(ii), state the effect ofthe polarity at the end of thesolenoid on the motion of thebar magnet.

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

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

(ii) Name the law that applies to(c)(i).

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

(d) Suggest one method to increasethe induced current in thesolenoid.

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

[1 mark]

Based on the direction of thecurrent in Diagram 6.1 and

Label the polarity at the end ofeach solenoid in box X and box

[2 marks]

Label the direction of motion ofthe bar magnet in Diagam 6.1

Based on the answers in 6(b)(i)and 6(b)(ii), state the effect ofthe polarity at the end of thesolenoid on the motion of the

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

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

Name the law that applies to

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

Suggest one method to increasethe induced current in 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 downwardsdirection.

(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-shapedlaminated 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 ABto the number of turns in the coilCD.

[ 2 marks ]

(d) The voltage supply 240 V.

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alternating current. is replaced bya voltage supply 240 V directcurrent.

(i) What happens to brightness ofthe bulb.

(ii) Give the reason for youranswer.

...

19.Question 4: Johor 2007Diagram 4.1 shows a simpletransformer used to light up a bulblabelled 24 V, 36 W.

When the mains supply isswitched on, the bulb isvery dim.

(a) State two ways in which thebrightness of the bulb can beincreased without changing thevoltage of the mains supply.

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

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

(b) Explain why the core is madefrom iron.

alternating current. is replaced bysupply 240 V direct

(i) What happens to brightness of

[1 mark ]

(ii) Give the reason for your

...[ 1 mark ]

Diagram 4.1 shows a simpletransformer used to light up a bulb

When the mains supply isswitched on, the bulb is

State two ways in which thebrightness of the bulb can beincreased without changing thevoltage of the mains supply.

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

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

plain why the core is made

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

(c) For the bulb operating at thenormal brightness, calculate:

(i) the current in the secondarycoil.

(ii) the current in the primary coil.Assume that the transformer isideal.

20.Question 6: Teknik 07Table 6 gives the details of twotransformers P and Q

TABLE 6

(a) Compare the number of turnsfor each transformers.

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

(b) Compare the voltages for eachtransformers.

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

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

For the bulb operating at thenormal brightness, calculate:

the current in the secondary

[2 marks]

the current in the primary coil.Assume that the transformer is

[2 marks]

Question 6: Teknik 07Table 6 gives the details of two

Compare the number of turnsfor each transformers.

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

Compare the voltages for each

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

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[1 mark]

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

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

.....................................................[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 typeof current applied to theprimary coil? Explain youranswer

[2 marks]

ESSAY QUESTIONS

21.Conceptual: Perak 07Diagram 10.1 and 10.2 showinsulated 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 paperclips 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 magnet placedon a stationary trolley. Figure 10.1(a)is the situation when the trolley isstationary while Figure 10.1(b) is thesituation when the trolley is movinginto the solenoid. Figure 10.2(a)shows a conductor which isstationary in the magnetic field whilefigure 10.2(b) shows the conductorbeing moved downwards in themagnetic field.

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

(ii) Observe Figure 10.1 and10.2, compare the galvanometerreadings when there is norelative motion between themagnet and the conductor andwhen there is relative motionbetween them. Relate thecurrent and the relative motionbetween the conductor and themagnetic field to deduce aphysic concept. Name thephysics concept that explainsthe above situation.

Figure 10.1 shows a magnet placedon a stationary trolley. Figure 10.1(a)

situation when the trolley isstationary while Figure 10.1(b) is thesituation when the trolley is movinginto the solenoid. Figure 10.2(a)shows a conductor which isstationary in the magnetic field whilefigure 10.2(b) shows the conductor

wnwards in the

(i) What is meant by magnetic

[1 mark]

Observe Figure 10.1 and10.2, compare the galvanometerreadings when there is norelative motion between the

uctor andwhen there is relative motionbetween them. Relate thecurrent and the relative motionbetween the conductor and themagnetic field to deduce aphysic concept. Name thephysics concept that explains

[5 marks]

23.Understanding : Perak 07Diagram 10.3 shows a simpleelectromagnet consists of a solenoidwith soft iron core inside. And, twomagnet bars are hung freely at bothsides of the solenoids.

Diagram 10.3

Explain what happens to magnet Pand magnet Q when the switch is on.

24.Understanding: MRSM 07Compare the structures, direction ofcurrent and changes in energy formsbetween a direct current generatorand an alternating current generator.

25.Understanding: SBP 07Diagram 12.1 shows twotransformers P and Q.

(i) What is meant by a transformer?

Understanding : Perak 07Diagram 10.3 shows a simpleelectromagnet consists of a solenoidwith soft iron core inside. And, twomagnet bars are hung freely at both

Diagram 10.3

ens to magnet Pand magnet Q when the switch is on.

[4 marks]

Understanding: MRSM 07Compare the structures, direction ofcurrent and changes in energy formsbetween a direct current generatorand an alternating current generator.

[4 marks]

Understanding: SBP 07Diagram 12.1 shows two

(i) What is meant by a 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 not100% 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 onthe 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 suppliedand 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 four types ofcables that are of the samelength.

Cable Diameter/cm

Density/kgm-3

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

You are asked to choose one ofthe cables to be used in theNational Grid Network. Explain thesuitability of each of thecharacteristics of the cables.Choose the most suitable cableand justify your choice.

[ 8 marks ]

29.Making decision: SBP 07The transmission of electricity ovethe National Grid Network uses highvoltage cables. You are assigned tostudy the characteristics of cableswhich could be used as transmissioncable. Table 12 shows thecharacteristics of four transmissioncables.

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 12;(i) Explain the suitability o

characteristics of the cablesto be used as transmissioncable.

(ii) Determine the most suitabletransmission cable to be

characteristics of four types ofcables that are of the same

ensity Rate ofexpan-

sionLowHighlow

You are asked to choose one ofthe cables to be used in theNational Grid Network. Explain the

bility of each of thecharacteristics of the cables.Choose the most suitable cable

[ 8 marks ]

Making decision: SBP 07The transmission of electricity overthe National Grid Network uses highvoltage cables. You are assigned tostudy the characteristics of cableswhich could be used as transmission

characteristics of four transmissioncables.

Rate ofthermalexpansionhighlowmediumhigh

Based on the table 12;(i) Explain the suitability of the

characteristics of the cablesto be used as transmission

(ii) Determine the most suitabletransmission cable to be

used and give reasons foryour choice.

30.Quantitative problem: SBP 07Diagram 12.1 shows twotransformers P and Q.

Calculate the output voltage of(i) transformer P(ii) (ii) transformer Q

31.Quantitative problem:Power of 15 kW is transmitted from asmall generator to a rural schoolalong 5000 m of cables ttotal resistance of 3 . The power istransmitted at the usual mains supplyvoltage of 240 V. Calculate;

(i) The current in the cables(ii) The power loss due to the heating

of the cables(iii) The percentage of loss of power

used and give reasons for

[10 marks]

Quantitative problem: SBP 07Diagram 12.1 shows two

Calculate the output voltage of

(ii) transformer Q

[ 4 marks ]

ve problem:kW is transmitted from a

small generator to a rural schoolof cables that have a

. The power istransmitted at the usual mains supply

Calculate;

The current in the cablesThe power loss due to the heating

The percentage of loss of power[5 marks]

FIZIKMOZAC 2010

32.Section C:Trengganu 07Diagram 12.1 shows an electric bell.

Diagram 12.1

(a) (i) State the energytransformation that takesplace when an electric bellrings.

(b) An electric bell is able to producea louder sound .Table 12 shows thecharacteristics of electric bellsP,Q,R,S and T which couldproduce a loud sound.

Electricbell

Size ofthehammer

Distancebetweenthehammerandgong/cm

Thenumberofturnsof thecoilaroundsoftironcore

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

Diagram 12.1 shows an electric bell.

Diagram 12.1

transformation that takesplace when an electric bell

[1 mark]

An electric bell is able to produce

characteristics of electric bellsP,Q,R,S and T which could

Thenumber

turnsof the

aroundsoftironcore

Curva-ture ofthegong

HighLowLowLow

You are asked to study the electricbells P,Q,R,S and T.Explain the suitability of eachcharacteristic of the electric bell inTable 12 and hence, determine whichelectric bell is able to produce theloudest sound.Justify your choice.

(c) Diagram 12.2 shows an electricbell 12 V,10 W is connected to theoutput of a transformer Theefficiency of the transformer is80%.

Calculate(i) the electric current in th

electric bell(ii) the electric current in the

primary coil

33.Section B: KDiagram 10.1 ana copper wire cplaced in a permThe magnetic ficatapult field.

You are asked to study the electric

Explain the suitability of eachcharacteristic of the electric bell inTable 12 and hence, determine which

ic bell is able to produce the

[10 marks]

Diagram 12.2 shows an electricbell 12 V,10 W is connected to theoutput of a transformer Theefficiency of the transformer is

the electric current in the

the electric current in the

[5 marks]

Section B: KDiagram 10.1 ana copper wire cplaced in a permThe magnetic fielantan 08d Diagram 10.2 show

arrying current isanent magnetic field.

eld produced is called

elantan 08d Diagram 10.2 show

arrying current isanent magnetic field.

eld produced is called

FIZIKMOZAC 2010

(a) What is meant by catapult field ?

(b) Using Diagram 10.1 and Diagram10.2, compare the number ofmagnet used, the angle ofdeflection of the cooper wire andthe angle of deflection ofammeter indicator.

(c) State the relationship betweenthe strength of the catapult fieldproduced and(i) number of magnet used

(ii) angle of deflection of copperwire

[2

(d) Diagram 10.3 shows a set upused to study the effects ofmagnetic field of a currentcarrying copper rod

(i) Explain what happens to thecopper rod when the switcis turned on

(ii) The dry cells are replacedwith 12 V a.c. Explain whathappens to copper rod whenthe switch is turned on.

[2

What is meant by catapult field ?[1 mark]

Using Diagram 10.1 and Diagram10.2, compare the number ofmagnet used, the angle ofdeflection of the cooper wire andthe angle of deflection of

[3 marks]

nship betweenthe strength of the catapult field

number of magnet used

angle of deflection of copper

[2 marks]

Diagram 10.3 shows a set upused to study the effects ofmagnetic field of a current-

n what happens to thecopper rod when the switch

[2 marks]

The dry cells are replacedwith 12 V a.c. Explain whathappens to copper rod whenthe switch is turned on.

[2 marks]

(e) Diagram 10.4 shows a d.c.electric motor .

Diagram 10.4

(i) Explain how the motor is able torotate.

(ii) Suggest three modificationsthat need to be done on the d.celectric motor to increase theefficiency of the motor. Give anexplanation for each suggestiongiven.

ows a d.c.

Diagram 10.4

Explain how the motor is able to

[4 marks]

modificationsthat need to be done on the d.celectric motor to increase theefficiency of the motor. Give an

for each suggestion

[6 marks]

FIZIKMOZAC 2010

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

(a) What is meant by directcurrent?

(b) Using the conceptof themagnetic effect of an electriccurrent, explain with the aid ofdiagrams how forces areproduced on a wire in the coil,as shown in Diagram 12.1.

(c) Diagram 12.2 shows thefeatures in the design of fourdirect current motors, P, Q, Rand S. You are required todetermine the most suitablemotor to lift a heavy objectsmoothly. Study the featuresof all the four motors- The density of the wires of

the coil- The number of turns of the

coil.- The strength of the magnet- The number of segments in

the commutatorExplain the suitability of thefeatures. Justify yourchoice.

Diagram 12.1 shows a simple direct

What is meant by direct

[1 mark]

Using the conceptof theetic effect of an electric

current, explain with the aid ofdiagrams how forces areproduced on a wire in the coil,as shown in Diagram 12.1.

[4 marks]

Diagram 12.2 shows thefeatures in the design of four

nt motors, P, Q, Rand S. You are required todetermine the most suitablemotor to lift a heavy objectsmoothly. Study the features

The density of the wires of

The number of turns of the

The strength of the magnethe number of segments in

Explain the suitability of thefeatures. Justify your

Model

Density

ofthecoil

Num

berofturns

ofthecoil

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 motor lifts aload of 3.0 N through a heightof 8.0 m in 5.0 s. Calculate,(i) the work done by t

motor in lifting the load,(ii) the useful output power

of the motor(iii) the efficiency of the

motor

Num

berofsegm

entsin

thecom

mutator

2 segments

4 segments

8 segments

8 segments

A 12 W electric motor lifts aload of 3.0 N through a heightof 8.0 m in 5.0 s. Calculate,

the work done by themotor in lifting the load,the useful output powerof the motorthe efficiency of the

[5 marks]

FIZIKMOZAC 2010

35.Melaka 08 section BDiagram 9.1 shows the pattern ofmagnetic field formed when currentflows in a coil. The magneticstrength is greater at the centercompared to the edge

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

(ii) Explain why the strength ofthe magnetic field is greaterat the center

(b) Diagram 9.2 and Diagram 9.3show the the magnetic fieldproduce when currentflows in a conductor.Diagram 9.4 shows the magneticfield produced when currentcarrying conductors inDiagram 9.2 and Diagram 9.3 isplaced in magnetic field

Diagram 9.1 shows the pattern ofmagnetic field formed when currentflows in a coil. The magnetic fieldstrength is greater at the center

(a) (i) What is meant by magnetic

[1 mark]

(ii) Explain why the strength ofthe magnetic field is greater

[3 marks]

(b) Diagram 9.2 and Diagram 9.3show the the magnetic field

Diagram 9.4 shows the magneticproduced when current

carrying conductors inDiagram 9.2 and Diagram 9.3 isplaced in magnetic field

(i) Based on Diagram 9.2 andDiagram 9.3, compare the

- pattern of the magnetic field- direction of the magnetic fie

(ii) Based on Diagram 9.2 ,Diagram9.3 and 9.4 compare the patternof the magnetic field

(iii) Based on Diagram 9.4 comparethe direction of the resultanceforces

(iv) Name one instrument whichuses the same principle as inDiagram 9.4. Explain thesimilarities.

(c) Diagram 9.5 shows a mcoil loudspeaker.

Based on Diagram 9.2 andDiagram 9.3, compare the

pattern of the magnetic fielddirection of the magnetic field

(ii) Based on Diagram 9.2 ,Diagram9.3 and 9.4 compare the patternof the magnetic fieldBased on Diagram 9.4 comparethe direction of the resultance

Name one instrument whichuses the same principle as inDiagram 9.4. Explain thesimilarities.

[5 mark]Diagram 9.5 shows a moving

FIZIKMOZAC 2010

You are required to give somesuggestions to design a movingloudspeaker which is functional andcan produce loud sound.Using the knowledge onelectromagnet, forces and theproperties of materials, explain thesuggestions based on the followingaspects ;(i) the shape of the magnet(ii) the position of the coil(iii) material used for the cone(iv) type of electrical supply(v) material used for the body of

the loudspeaker[10 marks

You are required to give somesuggestions to design a movingloudspeaker which is functional and

electromagnet, forces and theties of materials, explain the

suggestions based on the following

the shape of the magnetthe position of the coilmaterial used for the conetype of electrical supply

used for the body of

marks]

36.Section B:SBP 08(a) Diagram 10.1 and Diagram 10.2

show the relative motionbetween the magnet andsolenoid. Ends of the coils areconnected to a centregalvanometer.

Diagram 10.1

Diagram 10.2

Using Diagram 10.1 and Diagram10.2, compare:(i) the direction of the movement

of the magnet(ii) the deflection of the

galvanometer pointer(iii) Relate the movement of the

magnet, the polarity at the topof the coil and the force acts onthe magnet to deduce a relevantphysics law.

(b) Name the physics law thatdescribes the observations inDiagram 10.1 and Diagram10.2.

Diagram 10.1 and Diagram 10.2show the relative motionbetween the magnet andsolenoid. Ends of the coils areconnected to a centre-reading

Diagram 10.1

Diagram 10.2

Using Diagram 10.1 and Diagram

of the movement

of thealvanometer pointer

Relate the movement of themagnet, the polarity at the top

the force acts onthe magnet to deduce a relevant

[5 marks]

Name the physics law thatdescribes the observations inDiagram 10.1 and Diagram

[1 mark]

FIZIKMOZAC 2010

(c) Diagram 10.3 shows a directcurrent generator

Diagram 10.3

Explain how the above generatorworks to produce direct current.

(d) Diagram 10.4 shows a crosssection of a moving coilmicrophone. A microphoneconverts one form of energy intoanother.

Diagram 10.4

When the diaphragm moves inresponse to sound, the attached coilmoves in the magnetic field andgenerates a very small current in thewire of the coil.

Diagram 10.3 shows a direct

ram 10.3

Explain how the above generatorworks to produce direct current.

[4 marks]

Diagram 10.4 shows a crosssection of a moving coil

A microphoneconverts one form of energy into

Diagram 10.4

When the diaphragm moves inresponse to sound, the attached coilmoves in the magnetic field andgenerates a very small current in the

Using an appropriate concept inphysics, suggest and explain suitablemodifications or ways to enable themicrophone to detect soueffectively and generate biggercurrent based on the followingaspect:

(i) thickness of diaphragm(ii) strength of the material for

diaphragm(iii) number of turns of coil(iv) diameter of the wire of coil(v) strength of magnet

[10 marks

37.Section B:Melaka 09Diagram 10.1 and Diagram 10.2 showthe initial and the final position of acopper rod due to the formation of acatapult field that produce a force.

Using an appropriate concept inphysics, suggest and explain suitablemodifications or ways to enable themicrophone to detect soundeffectively and generate biggercurrent based on the following

thickness of diaphragmstrength of the material for

number of turns of coildiameter of the wire of coilstrength of magnet

10 marks]

Melaka 0910.1 and Diagram 10.2 show

the initial and the final position of ato the formation of a

catapult field that produce a force.

FIZIKMOZAC 2010

(a) What is meant by catapult field?

(b) Using Diagram 10.1 andDiagram 10.2, compare theangle of deflection of theammeter pointer , the powersupply and the distance movedby the copper rods.

[3

(c) State the relationship betweenthe strength of the force exertedon the copper rods and

(i) the moving distance of thecopper rods,

(ii) the size of electric current,[ 2

(d) Diagram 10.3 shows twocopper strips, WX and YZ,connected to a circuit.

What is meant by catapult field?[ 1 mark]

Using Diagram 10.1 andDiagram 10.2, compare theangle of deflection of the

pointer , the powersupply and the distance moved

[3 marks]

State the relationship betweenrength of the force exerted

on the copper rods andthe moving distance of the

the size of electric current,[ 2 marks]

Diagram 10.3 shows two thincopper strips, WX and YZ,connected to a circuit.

Explain what happens tocopper strip WX and YZ whenthe switch is closed.

(e) Diagram 10.4 shows a moving coilammeter

Explain how you would design amoving coil ammeter that canfunction better. In your explanation,emphasize the following aspects:

(i) the sensitivity of the ammeter,

(ii) the shape of the permanentmagnet,

(iii) the shape of the core,

(iv) the type of the core material,

(v) the type of the ammeter scale.

[ 10 marks]

[ 1

Explain what happens tocopper strip WX and YZ whenthe switch is closed.

[ 4 marks]

iagram 10.4 shows a moving coil

Explain how you would design aing coil ammeter that can

function better. In your explanation,emphasize the following aspects:

the sensitivity of the ammeter,

the shape of the permanent

the shape of the core,

the type of the core material,

mmeter scale.

FIZIKMOZAC 2010

38.Section B:Kelantan 09Diagram 10.1 and Diagram 10.2 showthe deflection of a galvanometerwhen a bar magnet are pushed intotwo identical solenoids.

(a) What is meant byelectromagnetic induction?

(b) Using Diagram 10.1 andDiagram 10.2,

(i) State the magnetic pole atend P when the barmagnets are pushed intothe solenoids.

(ii) Compare the number of thebar magnets and thedeflection of thegalvanometer.

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

magnets and the

Diagram 10.1 and Diagram 10.2 showthe deflection of a galvanometer

are pushed into

electromagnetic induction?Using Diagram 10.1 and

State the magnetic pole atend P when the barmagnets are pushed into

[1 mark]Compare the number of the

ar magnets and the

[2 marks]State the relationship between

The number of barmagnets and the

strength of the magneticfield

(ii) The strength of themagnetic filed and thedeflection ofgalvanometer

(d) Diagram 10.3 shows an idealtransformer.

(i) Name the type of transformer.

(ii) Explain how the current isinduced in the secondary coil.

(e) Diagram 10.4 shows agenerator.

strength of the magnetic

[1 mark]The strength of themagnetic filed and thedeflection of thegalvanometer

[1 mark]

Diagram 10.3 shows an ideal

Name the type of transformer.[1 mark]

Explain how the current isinduced in the secondary coil.

[3 marks]

Diagram 10.4 shows an a.c

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 theelectrical 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 Bduring reception of electricity bycustomers.

Physicalquantity

Transmission ofelectricity

Beforesubstation

A

Aftersubstation

ACurrent 80 A 15 A

PotentialDifference

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

Beforesubstation

B

Aftersubstation

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

FIZIKMOZAC 2010

Based on Diagram 10.1 andyour knowledge abouttransmission of electricalpower and other relatedphysics concepts, explain(i) The characteristics of

materials used to buildthe pylons.

(ii) The design of thepylons.

(iii) The characteristics ofthe cable used in theelectrical powertransmmission

[10 marks]

40. Section B:SBP 09(a) Diagram 10.1 and Diagram 10.2shows two identical electromagnet, Xand Y .

Diagram 10.1 Diagram 10.2

(i) What is meant byelectromagnet?

Based on Diagram 10.1 andyour knowledge abouttransmission of electricalpower and other relatedphysics concepts, explain

The characteristics ofmaterials used to build

The design of the

The characteristics ofthe cable used in theelectrical powertransmmission

[10 marks]

(a) Diagram 10.1 and Diagram 10.2shows two identical electromagnet, X

Diagram 10.1 Diagram 10.2

[ 1 mark ]

(ii) Using Diagram 10.1 and Diagram10.2 compare the current flow,the amount of ironthe magnetic field strength ofthe two electrodes. Relate thecurrent flow and amount of ironfiling attracted by theelectromagnet and the magneticfield strength.

(b) Diagram 10.3 shows a circuitbreaker.

Diagram 10.3

Explain how the circuit breakerworks.

[ 4 marks

Using Diagram 10.1 and Diagram10.2 compare the current flow,the amount of iron filing andthe magnetic field strength ofthe two electrodes. Relate thecurrent flow and amount of ironfiling attracted by the

lectromagnet and the magnetic

[ 5 marks ]

Diagram 10.3 shows a circuit

Diagram 10.3

Explain how the circuit breaker

marks]

FIZIKMOZAC 2010

(c) Diagram 10.4 shows an a.cgenerator

Diagram10.4

(i) Explain how the generatorworks 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]