MODUL F T 5 Keelektromagnetan 3 Electromagnetism · • Merancang dan menjalankan eksperimen untuk...

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MODUL • Fizik TINGKATAN 5

UN

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KeelektromagnetanElectromagnetism3

• Menyatakanapakahelektromagnet.State what an electromagnet is.

• Melukiskancorakmedanmagnetberdasarkanarusyangmengalirdalam:Draw the magnetic field pattern due to the current flow in a:(i) wayarlurus, (ii)gegelung, (iii)solenoid. straight wire, coil, solenoid.

• Merancangdanmenjalankaneksperimenuntukmengkajifaktoryangmempengaruhikekuatanmedanmagnetsuatuelektromagnet.Plan and conduct experiments to study factors that affect the strength of the magnetic field of an electromagnet.

• Menghuraikanaplikasielektromagnet./Describe applications of electromagnets.

3.1 Menganalisis kesan magnet bagi konduktor yang membawa arusAnalysing the magnetic effect of a current-carrying conductor

• Menghuraikanaruhanelektromagnet.Describe electromagnetic induction.

• Menentukanaraharusaruhandalam:Indicate the direction of the induced current in a:(i) wayarlurus/straight wire, (ii) solenoid/solenoid.

• Menerangkanfaktoryangmempengaruhimagnitudaruhanarus.Explain factors that affect the magnitude of the induced current.

• Menghuraikanaplikasiaruhanelektromagnet.Describe applications of electromagnetic induction.

• Membandingkanantaraarusterusdanarusulangalik.Compare direct current and alternating current.

3.3 Menganalisis aruhan elektromagnetAnalysing electromagnetic induction

• Menghuraikankesankepadakonduktoryangmembawaarusdalammedanmagnet.Describe what happens to a current-carrying conductor in a magnetic field.

• Melukiskancorakmedanmagnetgabunganberdasarkankonduktoryangmembawaarusdalammedanmagnet.Draw the pattern of the combined magnetic field due to a current-carrying conductor in a magnetic field.

• Menghuraikanbagaimanakonduktoryangmembawaarusdalammedanmagnetmengalamidaya.Describe how a current-carrying-conductor in a magnetic field experiences a force.

• Menerangkanfaktoryangmempengaruhimagnituddayayangterhasildalamkonduktoryangmembawaarusdalammedanmagnet.Explain the factors that affect the magnitude of the force produced in a current-carrying conductor in a magnetic field.

• Menghuraikanbagaimanagegelungpembawaarusdalammedanmagnetmengalamidayaputaran.Describe how a current-carrying coil in a magnetic field experiences a turning force.

• Menghuraikanprinsipkerjamotorarusterus.Describe how a direct current motor works.

• Menyatakanfaktoryangmempengaruhilajuputaranelektrikmotor.State factors that affect the speed of rotation of an electric motor.

3.2 Memahami daya terhadap konduktor yang membawa arus dalam medan magnetUnderstanding the force on a current-carrying conductor in a magnetic field

03-Physic F5 2015 (FSY4p).indd 102 10/15/15 11:31 AM

© Nilam Publication Sdn. Bhd.103


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• Menghuraikanstrukturdanprinsipoperasisuatutransformerringkas.Describe the structure and the operating principle of a simple transformer.

• Membandingkandanmembezakanantaratransformerinjaknaikdaninjakturun.Compare and contrast a step-up transformer and a step-down transformer.

• MenyatakanV

p

Vs

=N

p

Ns

untuktransformeryangideal.

State that V

p

Vs

= N

p

Ns

for an ideal transformer.

• MenyatakanVpI

p=V

sI

suntuktansformeryangideal.

State that Vp I

p = V

s I

s for an ideal transformer.

• Menghuraikantenagayanghilangdalamtransformer.Describe the energy losses in a transformer.

• Menghuraikancarauntukmeningkatkankecekapantransformer.Describe ways to improve the efficiency of a transformer.

• Menyelesaikanmasalahberkaitandengantransformer.Solve problems involving transformers.

3.4 Menganalisis transformerAnalysing transformers

• Menyenaraikansumbertenagayangdigunakanuntukmenjanaelektrik.List sources of energy used to generate electricity.

• Menghuraikanpelbagaicarauntukmenjanaelektrik.Describe the various ways of generating electricity.

• Menghuraikanpenghantaranelektrik.Describe the transmission of electricity.

• Menghuraikantenagayanghilangdalamkabelpenghantaranelektrikdankelebihanpenghantaranvoltantinggi.Describe the energy loss in electricity transmission cables and deduce the advantage of high voltage transmission.

• MenyatakankepentinganRangkaianGridKebangsaan.State the importance of the National Grid Network.

• Menyelesaikanmasalahberkaitanpenghantaranelektrik.Solve problems involving electricity transmission.

• Menerangkankepentingantenagayangbolehdiperbaharui.Explain the importance of renewable energy.

• Menerangkankesankepadaalamsekitaryangdisebabkanpenggunaanbeberapasumberuntukpenjanaantenagaelektrik.Explain the effects on the environment caused by the use of various sources to generate electricity.

3.5 Memahami penjanaan dan penghantaran elektrikUnderstanding the generation and transmission of electricity




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Hu

kum

gen

gg

aman

tan

gan

ka

nan

pad

a so

len

oid–untuk

menentukankutubsolenoid

Rig

ht-h

and

grip

rul

e fo

r –

sole

noid

to

det

erm

ine

the

pole

s of

a s

olen

oid

Putaranjarimengikutaraharus

Fin

gers

cur

l in

the

dire

ctio

n of

the

curr

ent

Ibujarimenunjukkankutubutara

The

thum

b po

ints

to N

pol

e

Way

ar lu

rus

Stra

ight

wir

eS

ole

no

idSo

leno

idG

egel

un

gC

oil

Med

an m

agn

etM

agne

tic fi

eld

Aru

s / C

urre

nt

Pro

du

ced

by

/ Dih

asilk

an o

leh

mas

uk

/ in

Araharus

Dir

ectio

n of

cur

rent

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elu

ng

/ C

oil

Per

atu

ran

skr

u M

axw

ell

Max

wel

l’s s

crew

rul

e

Jikaskrudiputarkan,arahgerakannyasam

aarahdenganarahaliranarus,arahputarannya

menentukanarahmedanmagnet.

If a

rig

ht-h

ande

d sc

rew

s is

turn

ed s

o th

at it

mov

es

forw

ards

in th

e sa

me

dire

ctio

n as

a e

lect

ric

curr

ent,

its

dire

ctio

n of

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atio

n gi

ves

the

dire

ctio

n of

the

mag

netic

fie

ld d

ue to

the

curr

ent.

No

te /

Not

a:Arahmedanmagnetyangmengelilingiwayarbolehditentukan

denganduakaedah:

The

dire

ctio

n of

the

mag

netic

fiel

d ar

ound

a w

ire

can

be d

eter

min

ed u

sing

tw

o ru

les:

Per

atu

ran

gen

gg

aman

tan

gan

kan

anT

he r

ight

-han

d gr

ip r

ule

Jikawayaryangmem

bawaarusdigenggam

oleh

tangankananmakaibujarimenghalasepanjang

dawaimenunjukkanaraharusdanjariyanglain

menunjukkearahmedanmagnetdisekeliling

dawai.

If a

wir

e ca

rryi

ng a

cur

rent

is g

ripp

ed w

ith th

e ri

ght

hand

, the

thum

b po

ints

alo

ng th

e w

ire

in th

e di

rect

ion

of

the

curr

ent a

nd th

e ot

her

finge

rs p

oint

in th

e di

rect

ion

of

the

mag

netic

fiel

d ar

ound

the

wir

e.

Arahmedanmagnet

Mag

netic

fiel

d di

rect

ion

Araharus

Dir

ectio

n of

cur

rent

Arahmedanmagnet

Mag

netic

fiel

d di

rect

ion

Araharus

Dir

ectio

n of

cur

rent

Arus

Cur

rent

Kom

pas

mem

plot

Plo

tting

co

mpa

ss

Garismedan

magnet

Mag

netic

fiel

d lin

es

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serbukbesi

Thic

k ca

rdbo

ard

spri

nkle

d w

ith ir

on fi

lings

Bekalan

voltan

rendah

Low

vol

tage

su

pply

Hu

kum

gen

gg

aman

tan

gan

kan

an

–untukmenentukanarahmedan

magnetyangdihasilkanoleharus

dalamwayarlurus

Rig

ht-h

and

grip

rul

e –

to d

eter

min

e th

e di

rect

ion

of th

e m

agne

tic fi

eld

prod

uced

by

a c

urre

nt in

a s

trai

ght w

ire

Garismedanmagnet

Dir

ectio

n of

cur

rent

(con

vent

iona

l)

Arahmedanmagnet

Dir

ectio

n of

mag

netic

fiel

d

Bekalan

voltan

rendah

Low

-vol

tage

su

pply

Solenoid

Sole

noid

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serbukbesi

Car

dboa

rd s

prin

kled

with

iron

filin

gs

N

S

+-

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ng

an

ali

sis

ke

san

ma

gn

et

ba

gi k

on

du

kto

r y

an

g m

em

ba

wa

aru

s A

naly

zing

the

mag

netic

eff

ect o

f a

curr

ent-

carr

ying

con

duct

or3

.1




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(a)Apabiladuawayarmem

bawaarusyangsamadandalamarahyang

sama,kekuatanmedanmagnetpaduanyangdihasilkanadalah

dua

kali

gand

adancorakyangdihasilkanadalah

sam

a.

W

hen

two

wir

es a

re c

arry

ing

the

sam

e cu

rren

t and

in th

e sa

me

dire

ctio

n, th

e

stre

ngth

of t

he r

esul

tant

mag

netic

fiel

d pr

oduc

ed is

do

uble

d a

nd th

e

patte

rn is

the

sa

me

.

Kek

uat

an m

edan

mag

net

ber

tam

bah

den

gan

The

str

engt

h of

the

mag

netic

fiel

d is

incr

ease

d by

:

(i)menggunakanarusyanglebih

besa

rdalam

gegelung.

us

ing

a bi

gger

cur

rent

thro

ugh

the

coil.

(ii)

men

amba

hkan

bilanganlilitangegelung

in

crea

sing

the

num

ber

of tu

rns

in th

e co

il

Ara

h m

edan

mag

net

dan

ko

mp

as m

emp

lot

The

dir

ectio

n of

the

mag

netic

fie

ld a

nd th

e pl

ottin

g co

mpa

ss

Arahjarumkom

pasmem

plot

menunjukkanarahmedan

magnet.

The

dire

ctio

n of

the

com

pass

ne

edle

indi

cate

s th

e di

rect

ion

of th

e m

agne

tic fi

eld.

So

len

oid

d

igab

un

gka

n

den

gan

ter

as b

esi

lem

bu

t. D

ipan

gg

il:C

ombi

ned

with

sof

t ir

on c

ore.

It i

s ca

lled:

Ele

ktro

mag

net

An

Ele

ctro

mag

net

d.c.

po

wer

su

pply

Bekalan

kuasa

a.t.

Clo

sed

switc

h

Suisditutup

Terasbesi

Daw

aikuprum

bertebat

Pinlukisan

Iron

cor

e

Insu

late

d co

pper

w

ire

Dra

win

g pi

n

Ap

likas

i ele

ktro

mag

net

App

licat

ions

of

elec

trom

agne

tism

•G

egan

tiel

ektr

omag

net

E

lect

rom

agne

tic r

elay

•Lo

ceng

ele

ktrik

E

lect

ric

Bel

l

•C

upin

gte

linga

tele

fon

Te

leph

one

ear-

piec

e

•P

emut

usli

tar

C

ircu

it br

eake

r

(a)Corakmedanmagnet

yangdihasilkanoleh

konduktoryangmem

bawa

arusbergantungpada

bent

uk konduktor.

Th

e pa

ttern

of m

agne

tic

field

pro

duce

d by

a c

urre

nt-

carr

ying

con

duct

or d

epen

ds

on th

e sh

ape

of t

he

cond

ucto

r us

ed.

(b)Garismedanmagnet

yang

lebi

hpa

dat

anta

ras

atu

Sam

ala

inmenunjukkan

med

anm

agne

tyan

g

lebi

hku

at.

Th

e m

agne

tic fi

eld

lines

whi

ch a

re

clos

er to

one

ano

ther

. rep

rese

nt a

st

rong

er m

agne

tic fi

eld

.(c)Garismedanmagnet

ditengahadalahlebih

padatantarasatu

samalaindisebabkan

berh

ampi

ran

de

ngan

aru

s

di

teng

ah

Th

e m

agne

tic fi

eld

lines

in

the

mid

dle

are

clos

er to

one

an

othe

r be

caus

e th

ey a

re n

eare

r to

the

curr

ent

in th

e m

iddl

e.

(a)Apabilaarusmengalirmelaluigegelung,teras

besilembutm

enjadi

elek

trom

agne

t.

W

hen

a cu

rren

t flow

s th

roug

h th

e co

il, th

e so

ft ir

on

core

bec

omes

an

ele

ctro

mag

net

.(b)Apabilaarusdalamgegelungdihentikan,teras

besilembutkehilangan

kem

agne

tann

ya.

W

hen

the

curr

ent i

n th

e co

il is

sw

itche

d of

f, th

e so

ft

iron

cor

e lo

ses

its

mag

netis

m.

(c)Kekuatanelektrom

agnetinibergantungkepada:

Th

e st

reng

th o

f the

ele

ctro

mag

net d

epen

ds o

n:

(i)

mag

nitu

dar

usy

ang

men

galir

mag

nitu

de o

f cur

rent

flow

(ii)

bila

ngan

lilit

an

num

ber

of tu

rns

(iii)

jeni

ste

ras

besi

type

of i

ron

core

(iv)

bent

ukte

ras

besi

the

shap

e of

the

iron

cor

e

+ -

Arusmengalirkeluardarikertas

Cur

rent

flow

s ou

t of t

he p

aper

Arusmengalirmasukkedalamkertas

Cur

rent

flow

s in

to th

e pa

per




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1 Perbandinganterasbesilembutdanterasbesikeluli. Comparison between soft iron core and steel core.

Teras besi lembutSoft iron core

Teras keluliSteel core

Mudah dimagnetkan dan dinyahmagnetkan

Easily magnetised and demagnetisedSusahdimagnetkandandinyahmagnetkanDifficult to be magnetised and demagnetised

Sesuaiuntukmenjadimagnet sementara

Suitable to be a temporary magnet (electromagnet)

Sesuaiuntukmenjadimagnet kekal

Suitable to be a permanent magnet

Terminologi Terminology

PeneranganExplanation

MedanmagnetMagnetic field

ialahkawasandimanabahanmagnetmengalamidaya

is a region in which a magnetic material experiences a force

ElektromagnetAn electromagnet

ialahmagnetsementarayangdiperbuatdaripadagegelungwayaryangmengelilingi

terasbesilembut

is a temporary magnet made by a coil of wire round a soft iron core

2

3 Faktor-faktoryangmempengaruhikekuatanmedanmagnetsuatuelektromagnet. Factors affecting the strength of the magnetic field of an electromagnet.

FaktorFactor


(a) Aruselektrik Electric current

Apabilaarus bertambah ,kekuatanmedanmagnet bertambah .

When the current is increased , the strength of the magnetic field increases .

(b) Bilanganlilitanwayar

Number of turns of wire

Apabilabilanganlilitanwayar bertambah ,makakekuatanmedanmagnet bertambah .

When the number of turns of wire is increased , the strength of the magnetic field increases .

(c) Jenisteras Type of material of

core

Terasyang berbeza mempunyaikekuatanmedanmagnetyang berbeza .

Terasbesilembut mempunyai medanmagnetyangpalingkuat .Terasbesi

lembutboleh menumpukangarisanmedanmagnet yangmelaluinya.Different materials of the core have different strengths of magnetic field. Soft iron core has the strongest magnetic field . A soft iron core is able to concentrate magnetic field lines through it.

(d) Bentukterasbesi

The shape of the iron core

TerasbesiberbentukU mempunyaimedanmagnetyanglebihkuat

daripada terasbesiyanglurus keranaterasbesiberbentuk-Umempunyaiduakutubyangbertentanganbersebelahanantarasatusamalaindanhasilnyagarismedanmagnettertumpudalamruangdiantaraduakutub.

A U-shaped iron core has a stronger magnetic field than the straight iron core because U-shaped iron core has two opposite poles adjacent to each other and as a result the magnetic field lines are concentrated in space between the poles.




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Menentukan kutub hujung solenoidDetermining the poles of a solenoid

Lihataraharusdarisetiaphujungsolenoid.Jikaaraharusmengikutarahjam,hujungsolenoidituialahkutubselatan.Jikaaraharusmengikutarahlawanjam,hujungnyaialahkutubutara.Look at the direction of the current from each end of the solenoid.If the direction of the current is clockwise, the viewed end of the solenoid is the south pole. If the direction of the current is anticlockwise, the viewed end is the north pole.

KutubselatanSouth pole

KutubutaraNorth pole

ArahikutjamClockwise

ArahlawanjamAnticlockwise

4 Melukiscorakmedanmagnetyangdisebabkanoleh:Draw the pattern of the magnetic field due to:

(a) ArusdalamwayarlurusCurrent in a straight wire

(b) ArusdalamgegelungtunggalCurrent in a single coil

(c) ArusdalamsolenoidCurrent in a solenoid

PenyelesaianSolution



N S




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Mengkaji hubungan antara kekuatan elektromagnet dengan arus

To investigate the relationship between the strength of an electromagnet and the current

Mengkaji hubungan antara kekuatan elektromagnet dengan bilangan lilitan solenoidTo investigate the relationship between the strength of an

electromagnet and the number of turns of the solenoid

InferensInference

Kekuatanelektromagnetbergantungkepada

magnitudaruselektrik.

The strength of an electromagnet depends on the

magnitude of the current.

Kekuatanelektromagnetbergantungpada

bilanganlilitansolenoid.

The strength of an electromagnet depends on the

number of turns of solenoid.

HipotesisHypothesis

Kekuatanelektromagnet(berdasarkanbilangan

pakuyangterlekatkepadaelektromagnet)

bertambahapabilaaruselektrikbertambah.

The strength of an electromagnet (indicated by the

number of nails attached to the electromagnet)

increases as the current increases.

Kekuatanelektormagnet(berdasarkanbilanganpaku

yangterlekatkepadaelektromagnet)bertambah

apabilabilanganlilitansolenoidbertambah.

The strength of an electromagnet (indicated by the number

of the nails attached to the electromagnet) increases as

the number of turns of solenoid increases.

TujuanAim

Untukmengkajihubunganantarakekuatan

elektromagnetdanarus.

To investigate the relationship between the strength of

an electromagnet and the current.

Untukmengkajihubunganantarakekuatan

elektromagnetdanbilanganlilitansolenoid.

To investigate the relationship between the strength of an

electromagnet and the number of turns of solenoid.

Pemboleh ubah dalam experimentVariables in the experiment

Pembolehubahdimanipulasi:arus

Manipulated variable: Current

Pembolehubahbergerakbalas:bilanganpaku

yangterlekatkepadaelektromagnet

Responding variable: The number of nails

attached to the electromagnet

Pembolehubahdimalarkan:bilanganlilitan

solenoid,jenisteras

Fixed variable: The number of turns of solenoid, type

of core

Pembolehubahdimanipulasi:bilanganlilitansolenoid

Manipulated variable: The number of turns of solenoid

Pembolehubahbergerakbalas:bilanganpaku

yangterlekatkepadaelektromagnet

Responding variable: The number of nails

attached to the electromagnet

Pembolehubahdimalarkan:arus,jenisteras

Fixed variable: current, type of core

Senarai bahan dan radasList of materials and apparatus

Ammeter,wayarpenyambung,reostat,kakiretort,suis,bekalankuasaa.t.,terasbesilembut,solenoid,pakubesikecildanbekasplastik.Ammeter, connection wires, rheostat, retort stand, switch, d.c. supply, soft iron core, solenoid, small iron nails and plastic container.

Ammeter,wayarpenyambung,reostat,kakiretort,suis,bekalankuasaa.t.,terasbesilembut,solenoid,pakubesikecildanbekasplastik.Ammeter, connection wires, rheostat, retort stand, switch, d.c. supply, soft iron core, solenoid, small iron nails and plastic container.

Susunan radasArrangement of the apparatus

SolenoidSolenoid

BekasplastikPlastic container

PakubesikecilSmall iron nails

TerasbesilembutSoft iron core

SolenoidSolenoid

BekasplastikPlastic container

Small iron nails


H H

Untuk menentukan kekuatan elektromagnetTo determine the strength of an electromagnet

EksperimenExperiment




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ProsedurProcedure

1 Suisditutup.

The switch is closed.

2 Bacaanammeterdirekodkan,l=0.1A

The reading of the ammeter is recorded,

I = 0.1 A.

3 Hujungbawahsolenoidditetapkanpada

jarak,H,daribekasplastikyang

mengandungipakubesikecil.

The lower end of the solenoid is fixed at a height, H,

from the plastic container full of small iron nails.

4 Bekasplastikdialihkandanbilanganpaku

yangterlekatkepadaelektromagnetyang

dikira=N.

The plastic container is removed and the

number of nails attached to the electromagnet

are counted = N.

5 Eksperimendiulangdengannilaiarus,yang

berbeza,I=0.2A,0.3A,0.4Adan0.5A

denganmelaraskanreostat.

The experiment is repeated with different

values of current, I = 0.2 A, 0.3 A, 0.4 A and

0.5 A by adjusting the rheostat.

1 Bilanganlilitansolenoiddirekodkan,M=5

The number of turns of solenoid is recorded, M = 5

2 Hujungbawahsolenoidditetapkanpadajarak,H,

dariyangmengandungipakubesi.

The lower end of the solenoid is fixed at a height, H,

from the container full of small iron nails.

3 Bekasplastikdialihkandanbilanganpaku

yangtertarikkepadaelektromagnetdikira=N.

The plastic container is removed and the number of nails

attached to the electromagnet is counted = N.

4 Eksperimendiulangdenganbilanganlilitan

solenoidyangberbeza,

M=10,15,20,25

The experiment is repeated with different

values of the number of turns of solenoid,

M = 10, 15, 20, 25

Penjadualan dataTabulation of data

Arus,/Current,I/A 0.1 0.2 0.3 0.4 0.5

Bilanganpakubesiyangterlekatkepada

elektromagnetNumber of iron

nails attached to the electromagnet, N

Bilanganlilitan,Number of turns,M

5 10 15 20 25

Bilanganpakubesiyangterlekatkepada

elektromagnetNumber of iron nails attached

to the electromagnet, N

Analisis dataAnalysis of the data

0 0

Bilanganpakubesiterlekat,Number of iron nails attached, N

Bilanganpakubesiterlekat,Number of iron nails attached, N

Arus,I/ACurrent, I /A

Bilanganlilitan,MNumber of turns, M




UN

IT 3

UN

IT 3

AP

LIK

AS

I EL

EK

TR

OM

AG

NE

TA

PP

LIC

AT

ION

S O

F E

LE

CT

RO

MA

GN

ET

S

Geg

anti

ele

ktro

mag

net

Gegantielektrom

agnetialahsuisyangdigunakanuntuk

men

gaw

al(suistutupataubuka)litarlainyangmem

punyai

arus

bes

ar(voltantinggi).Apabilasuisdihidupkan,

arus

yan

gke

cil

mengalirmelaluisolenoiddanterasbesi

lembutdimagnetkan.S

isi,X,armaturbesilem

but

tert

arik

ke

elektrom

agnet.Keadaaninim

enjadikanhujung,Y

,armaturbesilem

butyang

lainmenolakdanmenutupspringsesentuh.A

pabilasuisdipadamkan,tiada

arusmengalirdanterasbesihilang

kem

agne

tan

nya.Amaturbesi

lembutbalikkekedudukanasaldanlitarberkuasatinggiterbuka.

Ele

ctro

mag

netic

Rel

ay

An

elec

trom

agne

tic r

elay

is a

sw

itchi

ng d

evic

e us

ed to

co

ntro

l (

switc

h on

or o

ff) a

noth

er

circ

uit

that

has

a

larg

e cu

rren

t (

high

-vol

tage

or

dang

erou

s su

pply

). W

hen

the

switc

h is

on,

the

smal

l cur

rent

flow

s th

roug

h

the

sole

noid

and

the

soft

iron

cor

e is

m

agne

tised

. The

sid

e, X

, of t

he s

oft i

ron

arm

atur

e is

at

trac

ted

to th

e el

ectr

omag

net.

This

act

ion

mak

es th

e ot

her

end,

Y,

of th

e so

ft ir

on a

rmat

ure

push

and

clo

ses

the

cont

act.

Whe

n th

e sw

itch

is o

ff, n

o cu

rren

t

flow

s an

d th

e ir

on c

ore

lose

s its

m

agne

tism

. The

sof

t iro

n ar

mat

ure

retu

rns

to it

s or

igin

al p

ositi

on a

nd th

e po

wer

ful c

ircu

it is

ope

n.

Lo

cen

g e

lekt

rik

Apabilasuisditekan,arusmengalirmelaluisolenoiddanterasbesi

dim

agne

tkan

.Amaturbesilem

but

tert

arik

keelektrom

agnet.

Penukulmengetukgongdanlocengberbunyi.Springsesentuh

bergerakmenjauhisesentuh,litardiputuskan.Terasbesi

hila

ng

kem

agne

tann

ya.S

pringsesentuhmenyentuhskrusekalilagi,litar

tertutupsem

uladanarusmengalir.K

itaraniniberulang,asalkansuis

ditekan.

Ele

ctri

c be

llW

hen

the

switc

h is

pre

ssed

and

clo

sed,

the

curr

ent fl

ows

thro

ugh

the

sole

noid

and

the

iron

cor

e is

m

agne

tised

. The

sof

t iro

n ar

mat

ure

is

attr

acte

d to

the

elec

trom

agne

t. Th

e ha

mm

er s

trik

es th

e go

ng, t

hus

the

bell

ring

s. T

he s

prin

g co

ntac

t m

oves

aw

ay fr

om th

e co

ntac

t adj

ustin

g sc

rew

and

bre

aks

the

circ

uit.

The

iron

cor

e

lose

s it

s el

ectr

omag

netis

m. T

he s

prin

g co

ntac

t tou

ches

the

scre

w

agai

n, a

nd th

is c

lose

s th

e ci

rcui

t and

sw

itche

s on

the

curr

ent.

The

cycl

e re

peat

s ra

pidl

y as

long

as

the

switc

h is

pre

ssed

.

Kepingan

besilembut

Soft

iron

yok

e

Terasbesi

lembut

Soft

iron

cor

e

Gong/B

ell

Penukul/

Ham

mer

Armaturbesilem

but

Soft

iron

arm

atur

e

Skrupenyelarassesentuh

Con

tact

adj

ustin

g sc

rew

Sesentuh

Con

tact

s

Spring

Spri

ngs

Bateri

Bat

tery

Suistekan

Pus

h sw

itch

Litar

primer

Pri

mar

y ci

rcui

t

Litar

sekunder

Seco

ndar

y ci

rcui

t

Bekalanvoltanrendah

Low

vol

tage

su

pply

Baterikereta

Car

bat

tery

Pivot/

Piv

ot

Motor'pem

ula'

Star

ter

mot

or

Armaturbesilem

but

bentukL

L-sh

aped

sof

t iro

n ar

mat

ure

Springsesentuh

Spri

ng c

onta

cts

X

YSuis

Switc

hS N




UN

IT 3

UN

IT 3P

emu

tus

litar

/ C

ircu

it b

reak

er

Pem

utuslitarbekerjasam

asepertiw

ayar

fius

yangakan

mem

utuskanbekalankuasaapabila

arus

bes

armengalirmelalui

litar.A

pabilaarusterlalutinggi,daya

med

anm

agne

tm

enjadicukup

kuat

untukmenarikamaturbesilem

butdanmelepaskan

sentuhan.S

esentuhterpisahdanarusberhentimengalir.S

pringP

menjauhisesentuhsedikit.Apabilabutangresetditekan,springQ

menolakamaturbesilem

butbalikketempatasal.

Cir

cuit

brea

ker

A c

ircu

it br

eake

r w

hich

doe

s th

e sa

me

job

as a

fu

se w

ire

is d

esig

ned

to

disc

onne

ct th

e po

wer

sup

ply

whe

n th

ere

is to

o la

rge

a cu

rren

t fl

owin

g th

roug

h

a ci

rcui

t. W

hen

the

curr

ent g

ets

too

high

, the

m

agne

tic fi

eld

forc

e b

ecom

es

stro

ng e

noug

h to

pul

l the

sof

t iro

n ar

mat

ure

and

rele

ase

the

cont

acts

. Th

e co

ntac

ts a

re s

epar

ated

and

the

curr

ent s

topp

ed. T

he s

prin

g P

kee

ps th

e co

ntac

ts

apar

t. W

hen

the

rese

t but

ton

is p

ress

ed, s

prin

g Q

pus

hes

the

soft

iron

arm

atur

e ba

ck

to it

s or

igin

al p

ositi

on.

Cu

pin

g t

elin

ga

tele

fon

/ T

elep

ho

ne

ear-

pie

ce

Apabilakitabercakapmelaluimikrofontelefon,

tena

gab

unyi

ditukarkankepadaarusberubah-ubah(a.u).

Aru

s

berubah-ubahinim

engalirmasukkesolenoid.Terasbesilem

but

diel

ektr

omag

netk

andengan

keku

atan

berubah-ubah.

Diafragmabesiditarikoleh

elek

trom

agne

tdengandayayang

mem

punyaikekuatanberubah-ubah.D

iafragmabesibergetardengan

frekuensiyangsamadengangetaranarus.Getarandiafragmamenyebabkan

satusiri

mam

pata

ndan

reng

gang

anm

olek

uludara.

Gel

omba

ngb

unyi

yangdihasilkanmem

punyaifrekuensiyangsama

dengan

frek

uens

ibunyiyangasal.

Tele

phon

e ea

r-pi

ece

Whe

n a

pers

on s

peak

s th

roug

h a

tele

phon

e m

outh

pie

ce,

soun

d en

ergy

is c

hang

ed

to a

var

ying

ele

ctri

c cu

rren

t. W

hen

the

vary

ing

elec

tric

cur

rent

flow

s, th

e so

ft

iron

cor

e is

m

agne

tised

with

var

ying

st

reng

th.

The

elec

trom

agne

t p

ulls

on

the

diap

hrag

m. T

he d

iaph

ragm

vib

rate

s w

ith th

e

sam

e fr

eque

ncy

as

the

vary

ing

curr

ent.

The

vibr

atio

n of

the

diap

hrag

m c

ause

s

a se

ries

of

com

pres

sion

s a

nd

rare

fact

ions

of t

he a

ir m

olec

ules

. The

soun

d w

aves

are

pro

duce

d w

ith th

e sa

me

freq

uenc

y a

s th

e or

igin

al

soun

d.

Pem

utu

s lit

arC

ircu

it br

eake

r

Arusmengalirdarim

ikrofon

Cur

rent

flow

s fr

om m

icro

phon

e

Terasbesilem

but

Soft

iron

pol

e pi

ece

Magnetkekal

Per

man

ent m

agne

t

Diafragmaaloibermagnet

Mag

netic

allo

y di

aphr

agm

Solenoid

Sole

noid

Cu

pin

g t

elin

ga

tele

fon

Tele

phon

e ea

r-pi

ece

Kelitarrum

ahTo

hou

seho

ld

circ

uit

Spring,Q

Sesentuh

Con

tact

sAmaturbesilem

but

Soft

iron

arm

atur

e

Elektromagnet

Ele

ctro

mag

net

Wayarhidup

Live

Wir

ePangsiberspring,P

Piv

ot w

ith s

prin

g, P

Butangreset

Res

et b

utto

n

NS




UN

IT 3

UN

IT 3

1 Rajah di bawahmenunjukkan dua paku keluli yang digantung dengan dua benang elastik di dalam satugegelung.The diagram below shows two steel nails suspended from two elastic strings inside a coil of wire.

ApayangakanberlakukepadapakuapabilasuisKdihidupkan?Teranganjawapananda.What will happen to the nails when the switch K is turned on? Explain your answer.

Penyelesaian/ Solution

PakuakanmenolakantarasatusamalainThe nails will repel each other

Penerangan/Explanation

Keranaarusmengalirdalamarahyangsama;kutubXdanYadalahsamadanmenolaksatusamalain.KutubCdanDjugasama&menolaksatusamalain.Because of the same direction of current flow; the poles X and Y are the same and repel each other. The poles C and D are the same and repel each other.

2 Besilembutberbentuk-UmempunyaiduagegelungwayardililitkandihujunglenganPdanRsepertidalamrajah.A U-shaped soft-iron cylinder has two coils of wire wound on its ends P and R as shown in the diagram below.

P

R

Q


ApakahkutubmagnetyangdihasilkanpadakedudukanP,QdanR?What are the magnetic poles produced at positions P, Q and R?

P Q R

A Selatan/South Utara/North Selatan/South

B Selatan/South Utara/North Utara/North

C Utara/North Selatan/South Utara/North

D Utara/North Utara/North Selatan/South


JawapanCAnswer C

Penerangan/ExplanationDihujungPdanRarusmengalirdalamarahlawanjam.MakaPdanRadalahkutubutaramanakaladiQarusmengalirmengikutarahjam.MakaQadalahkutubselantan.At the ends P and R the current flows in the anticlockwise direction. So P and R are the north poles whereas at the end Q the current flows clockwise. So Q is the south pole.

[Perhatian:/Note: ]

GegelungCoil

PakukeluliSteel nail

BateriBattery

SuisKSwitch K

BenangelastikElastic string

C

X

D

Y

Latihan / Exercise




UN

IT 3

UN

IT 3

3 Dalamrajahdibawah,apabilasuisditutup,yangmanasatukahdaripadakompasmenunjukkanpesonganyangbetul?

(AbaikanmedanmagnetBumi)In the diagram below, when the switch is closed, which of the compasses shows the correct deflection?(Ignore the Earth’s magnetic field)


JawapanDAnswer D

Penerangan/ ExplanationPenghujungXmenjadikutubutara.Ymenjadikutubselatan.Pesongankompasadalahsamasepertiarahmedanmagnet.The end, X, becomes the north pole. Y becomes the south pole. Deflection of the compass is the same as the direction of the magnetic field.

TiubkadbodCardboard tube

Switch SelkeringDry cell

A

B C

D

TerminologiTerminology


DayamagnetMagnetic force

Merupakansatudayayangdikenakankeataskonduktoryangmembawaarusdalam

medanmagnet.

Is a force exerted on a conductor that carries a current in a magnetic field.

Medanlastik(Medanmagnetpaduan)Catapult Field(Resultant magnetic field)

Medanmagnetpaduanyangdihasilkanolehsalingtindakanantaramedanmagnetyang

dihasilkanoleharusdanmedanmagnetolehmagnetkekal.

Is the resultant magnetic field produced by interaction between the magnetic field produced by

current and magnetic field of the permanent magnet.

X Y

Memahami Daya pada Konduktor Pembawa Arus dalam Satu Medan Magnet Understanding the Force on a Current-Carrying Conductor in a Magnetic Field

3.2




UN

IT 3

UN

IT 3

Nota/Note:ArahdayamagnetbolehditentukanmenggunakanperaturantangankiriFleming.Direction of the magnetic force can be determined by using Fleming’s left-hand rule.

Corak medan magnet:Pattern of magnetic field:

(a) medanmagnetseragam dibahagiantengah

Uniform magnetic field in the middle

(b) medanmagnetyangtidakseragam ditepi

Non-uniform magnetic field at the side

Kekuatan medan magnet bergantung pada:The strength of the magnetic field depends on:

Nilaiarus yangmengalirMagnitude of the current

When there is interaction between the two magnetic fields

Apabila berlaku saling tindakan antara dua medan magnet

Medan magnet disebabkan oleh magnet magnadurMagnetic field due to magnadur magnets

Arus boleh ditingkatkan dengan:The current can be increased by:

(a) menambahkan d.g.ebekalankuasa.

increasing the e.m.f. of the power supply.

(b) menggunakanwayarsama

panjangyang lebihtebal .

using a thicker wire of the same length.

(c) menggunakan wayaryang

lebihpendek .

using a shorter wire .

Kekuatan medan magnet boleh ditingkatkan dengan:A stronger magnetic field can be produced by:

(a) menggunakan magnetyanglebihkuat ./using more powerful magnets .

(b) menggunakan duakepinganmagnet dengankutubyangsamabersebelahan.

using two pairs of magnets with like poles side by side.

(c) meletakkan magnetberdekatan antarasatusamalainuntukmengurangkan jarakantarakedua-duakutubmagnetitu.

placing the magnets closer to each other to narrow the gap between the poles of the magnet.

Wayar kuprum/Copper wire(a) Salingtindakandiantaramedanmagnetyangdihasilkanoleharus

elektrikdanmedanmagnetolehmagnetmagnadurmenghasilkandayamagnet .

The interaction between the magnetic field produced by the current and the

magnetic field of the magnadur magnet produces a magnetic force .

(b) Dayamagnet bertindakkeatas wayarkuprum.

The magnetic force exerts on the copper wire.

(c) Wayarkuprum bergerakkekanan .

The copper wire moves to the right .

Arahdaya,FDirection of Force, F

Araharus,IDirection of Current, I

Arahmedanmagnet,BDirection of Magnetic field, B

MedankuatStrong field

F

S

N

BesibentukUIron yoke

WayarkuprumCopper wire

KayupenahanWooden support

Bekalankuasavoltanrendah,arustinggiLow-voltage high-current power supply

Magnetmagnadur(kutubselatan)Magnadur magnet (south pole)

MagnetmagnadurMagnadur magnet

F

B N

Daya magnetMagnetic force

Medanmagnet

dihasilkanolehkonduktor

yangmembawaarusMagnetic field produced

by conductor carrying a current

Medanmagnet

olehmagnetkekalMagnetic field of the

permanent magnetsMedan magnet paduan dipanggil medan lastikResultant magnetic field is

called catapult field

MenghasilkanProduced

Corak medan magnet:Pattern of magnetic field:

(a) bulatansepusat

concentric circles (b) garismedan

magnetyangberdekatandengankonduktor

rapat antarasatusamalain

magnetic field lines nearer to the conductor

are closer to one another

DayayangdihasilkanmenolakwayarkekananForce produced pushes the wire to the right

N

S




UN

IT 3

UN

IT 3

1 Lukiscorakmedanlastik(medanmagnetpaduan)untuksetiapkesdibawah:Draw a pattern of the catapult field (resultant magnetic field) for each case below:(a) (b)

Penyelesaian/Solution

InferensInference

Magnituddayapadakonduktormembawaarusdalammedanmagnetbergantungkepada

magnitudarusyangmengalir

The magnitude of the force on a current-carrying conductor in a magnetic field depends on the magnitude

of the current

HipotesisHypothesis

Magnituddayapadakonduktoryangmembawaarusdalammedanmagnetbertambah

(ditentukanolehjarakgerakanwayarkuprumpendek)apabilamagnitudarusyangmengalir

bertambah(ditentukanolehmagnitudbezakeupayaan,V)

The magnitude of the force on a current-carrying conductor in a magnetic field (indicated by the distance of

movement of short copper wire) increases as the magnitude of the current increases (indicated by magnitude

of potential difference, V)

TujuanAim of the experiment

MengkajihubunganantaramagnituddayapadakonduktoryangmembawaarusdalammedanmagnetdenganmagnitudarusyangmengalirTo investigate the relationship between the magnitude of the force on a current-carrying conductor in a magnetic field with the magnitude of the current

Pemboleh ubahVariables in the experiment

Pembolehubahdimanipulasikan:Magnitudbezakeupayaan,V.

Manipulated variable: Magnitude of the potential difference, V.

Pembolehubahbergerakbalas:Jarakgerakanwayarkuprumpendek,L.

Responding variable: Distance of movement of short wire, L.

Pembolehubahdimalarkan:Kekuatanmedanmagnetkekal

Fixed variable: The strength of the permanent magnetic field

Senarai radas dan bahanList of apparatus and materials

Magnetmagnadur,deningbesiberbentukU,wayarkuprumyangtebal,wayarkuprumpendek,bekalankuasaa.t.(arusterus)danpembarisMagnadur magnets, U-shaped iron yoke, thick copper wire, short copper wire, d.c. supply and ruler

ArahdayalastikDirection of catapult force

ArahdayaDirection of force

ArahdayalastikDirection of catapult force

(a) (b)

S SN N

Eksperimen untuk menentukan magnitud daya saling tindakan atas konduktor pembawa arus dalam medan magnet kekalAn experiment to determine the magnitude of the catapult force on a current-carrying conductor in a permanent magnetic field


Contoh / Example




UN

IT 3

UN

IT 3


ProsedurProcedure

1. Voltanbekalankuasaa.t.yangdigunakandicatatkan;V=1.5V.Bekalankuasaa.t.dihidupkan. The voltage of the d.c. power supply used is recorded; V = 1.5 V. The d.c. power supply is switched on.

2. Jarakgerakanwayarkuprumpendekdiataswayarkuprumtebaldiukurdenganpembaris=L. The distance of movement of short copper wire on the thick copper wire is measured by a ruler = L.

3. Eksperimendiulangidenganbekalanbezakeupayaan,V=2.0V,2.5V,3.0Vdan3.5V. The experiment is repeated with different voltages of d.c. power supply, V = 2.0 V, 2.5 V, 3.0 V and 3.5 V.

Penjadualan dataTabulation of the data

Bezakeupayaan/Potential difference, V/V 1.5 2.0 2.5 3.0 3.5

Jarakgerakanwayar/Distance of movement, L/cm


DeningbesiberbentukUIron yoke

WayarkuprumpendekShort copper wire

WayarkuprumtebalThick copper wire

Bekalankuasaa.t.d.c. power supply


JenisType

MotorArusTerusDirect current motor

MeterGegelungBergerak(AmmeteratauVoltmeter)Moving-coil meters

RajahDiagram

MagnetkekalPermanent magnet

GegelungCoil

KomulatorCummulator

BeruskarbonCarbon brush

BeruskarbonCarbon brushBateri

Battery

PenunjukPointer

SkalaScale

SpringpengawalControl spring

AruskeluarCurrent out

ArusmasukCurrent in

GegelungkuprumCopper coil Bering

Bearing


SilinderbesilembutSoft iron cylinder

Jarakgerakan,Distance of movement,L/cm

Bezakeupayaan,Potentail difference,V/V0

Aplikasi daya saling tindakan pada konduktor yang membawa arus dalam satu medan magnet kekalApplications of a force on a current-carrying conductor in a permanent magnetic field




UN

IT 3

UN

IT 3

KawasanmedanmagnetlemahWeak magnetic field region

KawasanmedanmagnetkuatStrong magnetic field region

Bentuk medan lastikPattern of catapult field


(a) Salingtindakanantaramedanmagnetyangdihasilkanoleharusdanmedanmagnetolehmagnetkekal

menghasilkan medanmagnetpaduan(medanlastik) .The interaction between the magnetic field of the current and the magnetic field of the permanent magnet produces a

resultant magnetic field (catapult field) .

(b)Medanlastikinimenghasilkan dayagandingan (dalamarahyangbertentangan)danmenghasilkan

kesanputaran .

These catapult fields produce a couple of forces (are in

opposite direction) which produces a turning effect .(c)Gegelungberputarikutarahjam. The coil rotates in a clockwise direction.(d)Apabilagegelungmencapaikekedudukanmenegak,

sentuhanantaraberuskarbondankomutatorterputus,olehitutiadadayaputaranmemutarkangegelungitu

kerana tiadaarusmengalirdidalamnya . When the coil gets to the upright position, the contact

between the carbon brushes with the commutators is broken. Therefore there is no turning force on it because

no current flows in the coil.(e)Tetapigegelungmeneruskanputarandisebabkan

inersianya . But, the coil continues to rotate because of its inertia .

Putaranbolehditingkatkandengan:The turning effect can be increased by:

(a) meningkatkanmagnitud arusyangmengalir.

increasing the magnitude of the current.

(b) menambahkanbilangan lilitangegelung.

increasing the number of turns of the coil.

(c) menambahkankekuatan medanmagnetdenganmemasukkanterasbesilembut.

increasing the strength of the magnetic field by inserting the iron core.

(d) menambahkandiameter wayar.

increasing the diameter of the wire.

(a) Iaterdiridaripadagegelungkuprumsegiempattepatdenganbanyaklilitan,didalammedanmagnetbagimagnetkekal.

It consists of a rectangular copper coil of many turns pivoted in the magnetic field of a permanent magnet.

(b) Apabila arus,I, mengalir

melalui gegelung , daya putaranakanbertindakkeatasgegelung.

When the current, I, flows through the

coil , a turning force will be acting on the coil.

(c) Gegelungberputardanpenunjuk

terpesong kekedudukanbaruuntukmenunjukkanmagnitudarus,I,yangmengalirmelaluigegelungitu.

The coil turns and the pointer is

deflected to a new position to indicate the magnitude of the current, I, flowing through the coil.

(d) Apabila tiadaarusmengalir ,springpengawalmenarikgegelungkekedudukanasalsemuladanpenunjukterpesongsemulakesifar.

When there is no current flow , the control spring brings the coil back to its original position and the pointer goes back to zero deflection.




UN

IT 3

UN

IT 3

1 Rajahmenunjukkanrodtembagadiletakkandidalammedanmagnetbagimagnetkekal.

Dalam arah manakah rod tembaga itu bergerakapabilasuisditutup?The diagram shows a brass rod is placed in the magnetic field of a permanent magnet.In which direction does the brass rod move when the switch is closed?Penyelesaian/SolutionDenganmenggunakanperaturantangankiriFleming:DBy using Fleming’s left-hand rule: D

2 Rajahmenunjukkanarusmengalirdalamwayaryangtergantungantaraduakutubmagnet.

Dalamarahmanakahgerakanwayaritubergerak?The diagram shows a current flow in a wire hanging between the poles of a magnet.In which direction does the wire move?Penyelesaian/SolutionDenganmenggunakanperaturantangankiriFleming:CBy using Fleming’s left-hand rule: C

3 Rajahmenunjukkanarusmengalirdidalamkonduktormenembusipermukaankertas.

Dalam arah manakah daya bertindak ke ataskonduktor?The diagram shows a current flowing in a conductor in the direction into the page. Which is the direction of the force acting on the conductor?Penyelesaian/SolutionDenganmenggunakanperaturantangankiriFleming:ABy using Fleming’s left-hand rule: A

4 Rajahmenunjukkanwayarmembawaarusdiletakkanantaraduakutubmagnet.

Dalam arah manakah daya dapat menggerakkanwayar?The diagram shows a current-carrying wire placed between the poles of a magnet.In which direction will the force try to move the wire?Penyelesaian/SolutionDenganmenggunaperaturantangankiriFleming:ABy using Fleming’s left-hand rule: A

RodtembagaBrass rod

BartembagaBrass bar


MagnetMagnet

MagnetMagnet

KonduktorConductor

Contoh / Example




UN

IT 3

UN

IT 3

CARA YANG MENARIK UNTUK MENGINGAT BAGAIMANA MELUKIS PASANGAN DAYA LASTIKDALAMMOTORELEKTRIKAN INTERESTING WAY TO REMEMBER HOW TO DRAW THE COUPLE OF CATAPULT FORCES IN ANELECTRIC MOTOR

Klon Soalan Peperiksaan / Clone examination question :

Terangkanbagaimanasebuahmotorarusterusbolehmemutar.Explain how a direct currrent motor is able to rotate.

Penyelesaian/Solution :

Andaboleh jawabsoalan inidenganmelukissiri duagambar rajah,seperti yangditunjukkkan.Rajah (a)menunjukkansuperposisiduamedanmagnetyangberlainan.Rajah(b)menunjukkanhasilsalingtindakanantaraduamedanmagnetini.One of the ways to answer this question is two draw a series of two diagrams, as follows. Diagram (a) shows the superposition of two different magnetic fields. Diagram (b) shows the result of the interaction between these two magnetic fields.

SN

S

Dayalastik,FCatapult force, F

Dayalastik,FCatapult force, F

N

Rajah(a)Diagram (a)

Rajah(b)Diagram (b)

UntukmengingatcaramelukismedanlastikdalamRajah(b),To remember how to draw the catapult field in Diagram (b),

1. AndaikanandainginmemandukeretadarititikNketitikS. Imagine that you are driving a car from point N to point S.2. Apabilaandasampaikebulatanpekelilingpertama,ikutilaharahalirantrafikitu. When you reach the first roundabout, just follow the direction of the traffic flow of the first roundabout.3. Apabilaandasampaikebulatanpekelilingyangkeduaitu,ikutilaharahalirantrafikitujuga.Andaakan

sampaiketitikS. Then, when you reach the second roundabout, follow the direction of traffic flow of the second roundabout. You will then

arrive at point S.4. Akhirnya,andamestimenggambarkisahkan'medanlastik'itudiregangkansepertidalamsebuah

'katapult'ataulastik. Finally you need to think of the 'catapult field' as stretched rubber bands in a catapult.5. Iniakanmemberiarahbagipasangandayalastik,F,yangditunjukkanitu. This will give the directions of the couple of catapult forces, F, as shown.

NS

Motorarusterus(a.t.)A direct current (d.c.) motor

Tip Menjawab Soalan SPM




UN

IT 3

UN

IT 3

1 Rajahmenunjukkankonduktormembawaarusdidalammedanmagnetantara dua magnet kekal. Dalam arah manakah konduktor itu akanbergerak?The diagram shows a current-carrying conductor in a magnetic field between two permanent magnets. In which direction will the conductor be moved?

DenganmenggunakanPeraturantangan-kiriFleming,gerakankonduktoradalahkearahD.By Fleming’s left-hand rule, motion is towards D.

Penyelesaian/ SolutionJawapanD/Answer D

Penerangan/ Explanation

S N

B

D

CA

2 Antararajahberikut,yangmanakahmenunjukkandayayangbertindakkeataskedua-duakonduktormembawaarus?Which of the following diagrams shows the forces that act on the two parallel current- carrying conductors correctly?

A C

B D

Arusdalamkedua-duawayaradalahsamaarah.Olehitu,terdapatdayatarikan.VWakanmenarikMN.The currents in both wires are in the same direction. Hence, there is a force of attraction. VW will attract MN.



F

I

F

I

F

I

F

I

F

F F

I I

F F

F

I

F

I

V

V

V

V

W

W

W

W

M

M

M

M

N

N

N

N

3 Rajahmenunjukkan litar elektrik yang terdiri daripada sesiri sel kering,reostatdangegelungwayar.The diagram shows an electrical circuit consisting of a series of dry cells, a rheostat and a coil of wire.

Medanmagnetdidapatiwujuddisekitargegelung.Antaraberikut,yangmanakahbolehmeningkatkankekuatanmedanmagnet?A magnetic field is found to exist in the vicinity of the coil. Which of the following can increase the strength of the magnetic field?A Memasukkanterasbesilembutkedalamgegelung Insert an iron core into the coilB Meningkatkanrintanganpadaperintang Increase the resistance of the resistorC Menyambungkanselkeringsecaraselari Connect the dry cells in parallel

Penyelesaian/ SolutionJawapanA/Answer A


Kekuatanmedanmagnetbolehditingkatkandenganmemasukkanterasbesikedalamgegelung.Terasbesiinidimagnetkanapabilaarusmengalirdalamgegelungitu.The strength of the magnetic field can be increased by inserting an iron core into the coil. Ths iron core is being magnetized when there is a current flowing through the coil.

GegelungCoil

SelkeringDry cells

ReostatRheostat

Latihan / Exercise




UN

IT 3

UN

IT 3

4 Arus di dalam gegelung motor arus terus perlu diterbalikkan setiapsetengahputaransupayaThe current in the coil of a direct current motor needs to be reversed every half rotation so as toA mengekalkanputarandalamsatuarah maintain the rotation in one directionB menjanaarusulang-alik generate an alternating currentC mengekalkankelajuanputaran maintain a constant speed of rotationD mengekalkankekutubanmagnet maintain the polarities of the magnets



Komutatordalammotorarusterusmenyongsangkanaraharusyangmengalirdalamgegelungdanmengekalkanputarandalamsatuarah.The commutator in a d.c. motor reverses the direction of current flow in the coil to maintain the rotation in one direction.

Cadangan:/ Suggestion:

Lukissesiritigarajahbagiputarangegelung.Labelkanempatpenjurugegelungsebagaia,b,c,d.Iniakanmenjelaskansoalanini.Draw a series of three diagrams of the rotaion of the coil. Label the four corners of the coil as a, b, c, d. This will make things clearer for this question.

Penyelesaian/ SolutionJawapanC/Answer C


DenganmenggunakanPeraturantangan-kiriFleming,gegelungakanberputardalamarahlawanjam.By Fleming’s left-hand rule, the coil will rotate in an anticlockwise direction.

5 Gegelungwayar segi empat tepat diletakkan antara duamagnet kekalsepertiyangditunjukkandalamrajahdibawah.A rectangular coil of wire is placed between two permanent magnets as shown in the diagram below.

Apabilaarusmantap,ImengalirmelaluigegelungpadakomutatorPdanQ,apakahkesanyangdidapatipadagegelungitu?When a steady current, I, flows through the coil by way of commutators P and Q, what is the possible effect on the coil?A Daya bermagnitud yang sama bertindak ke atas kedua-dua sisi

gegelung dan menjadikan gegelung berada dalam kedudukanmendatar.

Forces of equal magnitude act on the two sides of the coil and keep the coil in the horizontal position.

B Gegelungakanberputarmengikutarahjam. The coil will rotate in a clockwise direction.C Gegelungakanberputarmengikutarahlawanjam. The coil will rotate in an anticlockwise direction.D Gegelung akan berputar dan kemudian berhenti dalam kedudukan

menegak. The coil will rotate and then stop in the vertical position.

NS




UN

IT 3

UN

IT 3

Un

tuk

men

gh

asilk

an a

rus

tera

ruh

:In

ord

er to

pro

duce

an

indu

ced

curr

ent:

(a)gerakan

konduktormesti

mem

otong

garis

med

anm

agne

t(flu

ksm

agne

t)

a

mov

ing

con

duct

or m

ust

cut

acro

ss t

he

mag

netic

fie

ld li

nes

(mag

netic

flux

).

(b)mesti

ada

perubahan

garis

med

anm

agne

tolehgegelung.

th

ere

mus

t be

a c

hang

e of

m

agne

tic

field

line

s li

nkag

e w

ith a

coi

l.

No

ta/N

ote:

Untukmenentukanarah

arusteraruhyangmengalir

dalamkonduktoryang

digerakandalamsatu

medanmagnet,

peraturantangan-kanan

Fleming

(PeraturanDinam

ik):

To d

eter

min

e th

e di

rect

ion

of a

cur

rent

indu

ced

ina

cond

ucto

r, F

lem

ing'

sri

ght-

hand

rul

e is

use

d(D

ynam

o R

ule)

:

Galvanometer

Gal

vano

met

er

Wayar

Wir

e

Galvanometer

Gal

vano

met

er

Barmagnet

Mag

net b

ar

Solenoid

Sole

noid

(a)Pem

otonganfluks

magnet

C

uttin

g of

mag

netic

flu

x

(b)Perubahanfluksoleh

gegelung

C

hang

e of

flux

ling

kage

w

ith th

e co

il

Aru

han

Ele

ktro

mag

net

/ E

lect

rom

agne

tic I

nduc

tion

Ter

min

olo

gi /

Ter

min

olog

yP

ener

ang

an /

Exp

lana

tion

Aruhanelektrom

agnet

Ele

ctro

mag

netic

indu

ctio

n

Ialahpenghasilanaruselektrikteraruhdalamsuatukonduktoryangberadadi

med

anm

agne

tyangberubah-

ubah./I

s th

e pr

oduc

tion

of a

n in

duce

d el

ectr

ic c

urre

nt in

a c

ondu

ctor

whi

ch is

in a

cha

ngin

g m

agne

tic fi

eld

.

Arusaruhan

Indu

ced

curr

ent

Terhasilapabilaterdapatgerakan

rela

tifantarakonduktoratausolenoiddenganmedanmagnet.

Is p

rodu

ced

whe

n th

ere

is a

re

lativ

e m

otio

n be

twee

n co

nduc

tor

/sol

enoi

d an

d th

e m

agne

tic fi

eld.

Dayagerakelektrikteraruh(d.g.e.teraruh)

Indu

ced

elec

trom

otiv

e fo

rce

(ind

uced

e.m

.f.)

Ialahd.g.e.yangterhasilantarahujungkonduktorbergerakatausolenoiddenganmagnetkekal

Is th

e e.

m.f.

pro

duce

d be

twee

n th

e en

ds o

f the

mov

ing

cond

ucto

r / s

olen

oid

and

the

perm

anen

t mag

net

Hukum

Faradaytentangaruhan

electrom

agnet

Far

aday

’s L

aw o

f ele

ctro

mag

netic

indu

ctio

n

Men

yata

kan

baha

wa

mag

nitu

dd.

g.e.

tera

ruh

berk

adar

lang

sung

den

gan

kada

r

peru

baha

nflu

ksm

agne

tata

uka

dar

pem

oton

gan

fluks

mag

net.

The

mag

nitu

de o

f the

indu

ced

elec

trom

otiv

e fo

rce

(e.m

.f.)

is d

irec

tly p

ropo

rtio

nal t

o th

e ra

te o

f

chan

ge o

f mag

netic

flux

or

the

rate

of c

uttin

g th

e m

agne

tic fl

ux.

Hukum

Lenz

Lenz

’s L

aw

Men

yata

kan

baha

wa

arus

aru

han

sent

iasa

men

galir

pad

aar

ahy

ang

men

enta

ng

peru

baha

nflu

ksm

agne

tyan

gm

engh

asilk

ana

rus

aruh

anin

i.

Stat

es th

at a

n in

duce

d cu

rren

t alw

ays

flow

s in

suc

h a

dire

ctio

n so

as

to o

ppos

e th

e ch

ange

of m

agne

tic

flux

prod

ucin

g th

is in

duce

d cu

rren

t.

Me

ng

an

ali

sis

Aru

ha

n E

lek

tro

ma

gn

et

Und

erst

andi

ng E

lect

rom

agne

tic I

nduc

tion

3.3




UN

IT 3

UN

IT 3

Mag

nitu

dd.g.e.aruhandan

arah

arusteraruhboleh

ditentukanmenggunakanhukum

LenzdanhukumFaraday.

The

mag

nitu

de o

f the

indu

ced

e.m

.f. a

nd

dire

ctio

n o

f the

indu

ced

curr

ent

can

be d

eter

min

ed b

y ap

plic

atio

n of

Len

z's

law

and

Far

aday

's la

w.

Hu

kum

Len

z L

enz’

s L

aw

Untukmenentukan

arah

arusteraruh

To d

eter

min

e th

e di

rect

ion

of t

he in

duce

d cu

rren

t

Apabilamagnetdigerakan

men

deka

tisolenoid,arusdiaruhkandidalam

solenoid,m

akahujungPmesti

diaruhkanuntukmenjadikutub

utar

amaka

daya

tola

kan

wujudantarasolenoiddanmagnet.

[Perhatian:MengikutH

ukum

Lenz,Pmenjadikutubutarauntuk

men

enta

nggerakanmagnet

mas

ukk

eda

lam

solenoid]

Apabilamagnetdigerakan

men

jauh

isolenoid,hujungPdiaruhkanuntukmenjadikutub

sela

tan

,maka

daya

tarik

anwujudantarasolenoiddanmagnet.

Olehitu,apabilamagnetbergerakmendekatiataumenjauhisolenoid,kerjadilakukanuntukmengatasaidaya

yangbertentangan.kerjayangdilakukanditukarkankepadatenagaelektrikyangmenghasilkan

arus

aru

han

.Tandakandenganjelas(padarajahdiatas)araharusaruhan

Whe

n th

e m

agne

t is

mov

ed

tow

ards

the

sole

noid

, cur

rent

is in

duce

d in

the

sole

noid

. hen

ce th

e en

d P

mus

t be

indu

ced

to

beco

me

the

nort

h p

ole

so th

at a

fo

rce o

f rep

ulsio

n e

xist

s be

twee

n th

e so

leno

id a

nd th

e m

agne

t.[N

ote:

Acc

ordi

ng to

Len

z’ L

aw, P

bec

omes

the

nort

h po

le s

o as

to

appo

se th

e m

otio

n of

the

mag

net f

rom

en

terin

g t

he s

olen

oid]

Whe

n th

e m

agne

t is

mov

ed

away

from

the

sole

noid

, the

end

P is

indu

ced

to b

ecom

e th

e so

uth

pol

e so

th

at a

fo

rce o

f attr

actio

n e

xist

s be

twee

n th

e so

leno

id a

nd th

e m

agne

t. Th

eref

ore

whe

n th

e m

agne

t is

mov

e to

war

ds o

r aw

ay fr

om a

sol

enoi

d, w

ork

mus

t be

done

to o

verc

ome

the

oppo

sing

forc

e. th

e w

ork

done

is c

onve

rted

into

ele

ctri

cal e

nerg

y w

hich

cre

ates

the

indu

ced

curr

ent

.In

dica

te c

lear

ly (

in th

e di

agra

m)

the

dire

ctio

n of

indu

ced

curr

ent

Hu

kum

Aru

han

Ele

ktro

mag

net

Law

s of

Ele

ctro

mag

netic

Ind

uctio

n

Hu

kum

Far

aday

Far

aday

’s L

aw

Untukmenentukan

mag

nitu

darus

teraruh

To d

eter

min

e th

e m

agni

tude

of t

he

indu

ced

curr

ent

Ber

das

arka

n H

uku

m F

arad

ay:

Bas

ed o

n F

arad

ay’s

Law

:A

rus

aruh

ana

tau

d.g.

ear

uhan

boleh

ditingkatkanjika:

The

indu

ced

curr

ent o

r in

duce

d e.

m.f

can

be

incr

ease

d if:

(a)

bila

ngan

lilit

ansolenoid

bertam

bah.

th

e nu

mbe

r of

turn

s o

f the

sol

enoi

d in

crea

ses.

(b)

keku

atan

magnetbertambah.

th

e st

reng

th o

f the

mag

net i

ncre

ases

.

(c)

laju

ger

akan

rel

atif

antara

magnetdansolenoidbertam

bah.

th

e sp

eed

of r

elat

ive

mot

ion

bet

wee

n th

e m

agne

t and

sol

enoi

d in

crea

ses.

PQ

PQ

Dayagerakan,M

Mot

ion,

MMedanmagnet,B

Mag

netic

fiel

d, B

S

Arusaruhan

Indu

ced

curr

ent,

I

N




UN

IT 3

UN

IT 3

RajahDiagram

Gerakan relatifRelative motion

Rajah menunjukkan arus teraruh dihasilkanDiagram shows the induced current occurs

Arusaruhandihasilkanapabila:Induced current is produced when:

(a) Gerakkanmagnet kedalamsolenoidyangpegun,ataugerakkanmagnetmelintasiwayaryangpegun.

Moving the magnet into a stationary solenoid or moving the magnet over a stationary wire.

(b) Gerakkan wayar/solenoid melintasimagnetpegun.

Moving the wire / solenoid over a stationary magnet.

(c) Gerakanmagnetdanwayar/solenoiddalam

arahbertentangan . Moving magnet and wire / solenoid in

the opposite directions .(d) Gerakanmagnetdanwayar/

solenoiddalam arah

yangsama tetapipadalajuberbeza.

Moving the magnet and wire / solenoid

in the same direction but at different speeds.

Galvanometerakanterpesong.The Galvanometer will show a deflection.

Arusteraruhdihasilkanapabila:Induced current is produced when:

(a) Menutup dan membuka suisS.

Closing and opening switch S.

(b) MelaraskanreostatR. Adjusting rheostat R.(c) GerakkangegelungP

mendekati atau

menjauhi gegelungQ.

Moving the coil P nearer to

or further from the coil Q.

Galvanometerakanterpesong.The galvanometer will show a deflection.

MagnetbarBar magnet

GalvanometerberpusatsifarCentre-zero galvanometer

SolenoidSolenoid




Deningbesibentuk-UIron yoke

P Q

R

S

P

S

R

Q

Mekanisma penghasilan arus teraruh atau d.g.e teraruh:Mechanism of the production of induced current or induced e.m.f.:

Apabilagerakanrelatifantarakonduktordanmagnetdilakukan,konduktorakan memotong garismedan

magnetdan mengubahfluksmagnet .

Whenever there is a relative motion between a conductor and a magnet, the conductor cuts across the magnetic lines of force

and changes the magnetic flux .

Gerakan relatif untuk menghasilkan arus teraruhRelative motion to produce induce currents




UN

IT 3

UN

IT 3

InferensInference

Magnitudarusteraruhbergantungkepadalajugerakanrelatifantaramagnetdankonduktor.

The magnitude of an induced current depends on the speed of the relative motion between the conductor and

magnet.

HipotesisHypothesis

Lajugerakanrelatifantaramagnetdankonduktorbertambah(diukurmelaluiketinggian

magnetdiatassolenoid),makamagnitudarusteraruhbertambah.

As the speed of the relative motion between the conductor and magnet increases (indicated by height of the

magnet above the solenoid), the magnitude of the induced current also increases.

TujuanAim of the experiment

Mengkajihubunganantaralajugerakanrelatifantaramagnetdankonduktordenganmagnitudarusteraruh.To investigate the relationship between the speed of the relative motion between the conductor and magnet and the magnitude of an induced current.

Pemboleh ubahVariables in the experiment

Pembolehubahdimanipulasikan:Lajugerakanrelatifantarakonduktordanmagnet.Lajuinidiwakili

olehketinggianmagnetdiatassolenoid,H,sebelummagnetdilepaskan.

Manipulated variable: The speed of the relative motion between the conductor and magnet. This speed is

represented by the height, H, of the magnet above the solenoid, before it is released.

Pembolehubahbergerakbalas:Magnitudarusteraruh

Responding variable: The magnitude of the induced current

Pembolehubahdimalarkan:Bilanganlilitansolenoiddankekuatanmagnet

Fixed variable: Number of turns of solenoid and the strength of the magnet

Senarai radas dan bahanList of apparatus and materials

Galvanometerberpusatsifaryangsensitif,solenoid,magnetbardanpembaris.Sensitive zero-centre galvanometer, solenoid, bar magnet and ruler.



LadungBob

MagnetbarBar magnet

MagnetbarBar magnet

KonduktorConductor

(d) Menggantikanbateridengan

bekalan kuasaarus ulang-alikdansuisSditutup.

Replacing the battery with a.c. power supply and close

the switch.

Arusteraruhdihasilkanapabila:Induced current is produced when:

mengayunkan banduldi

dalam medanmagnet .oscillating the pendulum bob in

a magnetic field .

Gavanometerakanterpesong.The galvanometer will show a deflection.

Eksperimen untuk menentukan magnitud arus teraruhAn experiment to determine the magnitude of an induced current





UN

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UN

IT 3


ProsedurProcedure

1. Ketinggianmagnetdiatassolenoiddiukurdenganpembaris,H=2.0cm.

The height of the magnet above the solenoid is measured by a ruler, H = 2.0 cm.

2. Magnetdijatuhkankedalamsolenoiddanbacaangalvanometerdicatatkan=I.

The magnet is dropped into the solenoid and the reading of the galvanometer is recorded = I.

3. Eksperimendiulangidenganketinggianmagnetdiatassolenoidyangberbeza,

H=4.0cm,6.0cm,8.0cmdan10.0cm.

The experiment is repeated with different heights of the magnet above the solenoid, H = 4.0 cm, 6.0 cm,

8.0 cm and 10.0 cm.

Penjadualan dataTabulation of the data

Ketinggianmagnet/Height of magnet, H/cm 2.0 4.0 6.0 8.0 10.0

Arusteraruh/Induced current, I/μA


ArusteraruhInduced current I/μA

KetinggianmagnetHeight of magnetH/cm0

PembarisRuler

SolenoidSolenoid

PaipPVC(ataukadbod)PVC (or cardboard) pipe

MagnetbarBar magnet




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Penjana Arus Terus / D.C. Generator Penjana Arus Ulang-alik / A.C. Generator

(a) Apabilaangker/gegelungsatahdalamkeadaan

menegak ,sisiBCdanADbergerakselari

dengangarismedanmagnet.Maka, tiada

pemotongangarismedanmagnet .

Maka,tiada arusaruhan dihasilkan.

When the plane of the coil is in a vertical position, the sides BC and AD move parallel with the magnetic field lines.

There is no cutting of magnetic lines of force .

Therefore, no induced current is produced.

(b)Dalamkeadaan mendatar ,BCbergerakke

atasdanADbergerakkebawah.SisiBCdanAD

memotonggarismedanmagnet padasudut

tepat.Olehitu, arusteraruh yangmaksimumdihasilkansertad.g.e.maksimumdiaruhkan.

In the horizontal position, BC moves upwards and AD

moves downwards. The sides BC and AD cut the magnetic

field lines at right angles. Hence, the induced

current produced is maximum and the induced e.m.f. is maximum.

(a) Bermuladengangegelungsatah/angkerdalam

keadaanmenegak ,sisiBCdanADbergerakdalamkeadaanselaridengangarismedanmagnet.Maka,tiadapemotongangarismedanmagnet.Maka,

tiada arusaruhan dihasilkan.

Starting with the plane of the coil in the vertical

position , the sides BC and AD move parallel with the magnetic field lines. There is no cutting of magnetic lines of

force. Therefore, no induced current is produced.(b)Dalamkeadaanmendatar,BCbergerakkeatasdan

ADbergerakkebawah.SisiBCdanADmemotong

garismedanmagnet padasuduttegak.Olehitu,arusteraruhdand.g.e.teraruhyang

maksimum dihasilkan. In the horizontal position, BC moves upwards and AD moves

downwards. The sides BC and AD cut the magnetic

field lines at right angles. Hence, the induced

current produced is maximum and the induced e.m.f. is

maximum.

A

A

B

BQ P Q P

B

B

A

AQ P Q P

A

B

Q P

A

B A A B

B

B

A

A

B

NS

GelanggelincirSlip rings

AB

C D


Gegelungsatah/angkerCoil


GalvanometerGalvanometer

PutaranRotation


KomutatorCommutatorGegelungsatah/angker

Coil



ArusCurrent

PutaranRotation

LitarluarExternal circuit

LitarluarExternal circuit

N

Q

S

P

AB

C D

A

A

B

BQ P Q P

B

B

A

AQ P Q P

A

B

Q P

A

B A A B

B

B

A

A

B

A

A

B

BQ P Q P

B

B

A

AQ P Q P

A

B

Q P

A

B A A B

B

B

A

A

B(a)

d.g.e.=0e.m.f. = 0

(b)d.g.e.=

maksimume.m.f. =

maximum

(c)d.g.e.=0e.m.f. = 0

(d)d.g.e.=

maksimume.m.f. =

maximum

(e)d.g.e.=0e.m.f. = 0

d.g.eteraruhinduced e.m.f.

BilanganputaranNumber of rotations0

A

A

B

BQ P Q P

B

B

A

AQ P Q P

A

B

Q P

A

B A A B

B

B

A

A

B(a)

d.g.e.=0e.m.f. = 0

(b)d.g.e.=

maksimume.m.f. =

maximum

(c)d.g.e.=0e.m.f. = 0

(d)d.g.e.=

maksimume.m.f. =

maximum

(e)d.g.e.=0e.m.f. = 0

d.g.eteraruhinduced e.m.f.

BilanganputaranNumber of rotations

0

Aplikasi Aruhan ElektromagnetApplications of Electromagnetic Induction




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(c)Selepaskeadaanini,arusteraruh(d.g.e.teraruh)

berkurangan sehinggakesifarapabilaangker/gegelungsatahdalamkeadaanmenegaksemula

kerana tiadapemotongan garismedanmagnet.

After this position, the current starts to decrease until it is zero when the plane of the coil is in a vertical position

because the magnetic field lines are not cut .

(d) Araharus didalamlitarluartidakberubah.

The direction of the current in the external circuit does not change.

(e)Prosesinidiulang. The process is repeated.

(f) Arusdalamlitarluarialah arusterus

(iaitu,arusyangmengalirdalamsatuarah).

The current in the external circuit is a direct current

(that is, the current flows in one direction).

(c)Selepaskeadaanini, arusteraruh (d.g.e.

teraruh) berkurangan sehinggakesifar,apabila

angker/gegelungsatahdalam keadaanmenegak semulakeranatiadapemotongangarismedanmagnet.

After this position, the current starts to decrease until it is zero when the plane of the coil is

in a vertical position because the magnetic field lines are not cut.

(d)Prosesinidiulang. The process is repeated.

(e) Araharus didalamlitarluar

berubah-ubah setiapkaligegelung/angkermelepasikeadaanmenegak.

The direction of the current in the

external circuit changes each time the coil passes the vertical position.

(f) Arusdalamlitarluarialah arusulang-alik .

The current in the external circuit is an alternating current .

Arusteraruhdihasilkanjikaterdapatgerakanrelatifantaramagnetbardansolenoid.SituasiDtidakadagerakanrelatif.An induced current is produced if there is relative motion between the bar magnet and the solenoid. The situation in D does not have any relative motion.



1 Rajahmenunjukkansolenoiddanmagnet.The diagram shows a solenoid and a magnet.

Antara tindakan berikut, yang manakah tidak menunjukkan pesonganpadagalvanometer?Which of the following actions will not produce a deflection in the galvanometer?A Magnetditolakkedalamsolenoid. The magnet is pushed into the solenoid.B Solenoidbergerakkearahmagnet. The solenoid is moved towards the magnet.C Magnetdikeluarkandarisolenoid. The magnet is moved out of the solenoid.D Kedua-duamagnet dan solenoid digerakkan ke kiri pada kelajuan

0.2ms–1. Both the magnet and solenoid are moved to the left at a speed of 0.2 m s–1.

Magnet Solenoid

Latihan / Exercise




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3 Rajahmenunjukkanrodkuprumyangdisambungkankepadagalvanometerdandiletakkanantaraduamedanmagnetkekal.The diagram below shows a copper rod which is connected to a galvanometer and placed between two permanent magnets.

ApakaharahgerakanroduntukmenghasilkanarusyangmengalirmelaluiroddarihujungPkeQ?What is the direction of the movement of the rod to produce a current that flows through the rod from its end P to Q?

2 Rajah menunjukkan gegelung mendatar, disambungkan kepadagalvanometer dan diletakkan antaramagnet magnadur yang berlainankutub.The diagram shows a horizontal coil, connected to a galvanometer, placed between the opposite poles of two magnadur magnets.

Antaraaktivitiberikut,yangmanakahakanmenghasilkanarusteraruh?Which of the following activities will produce an induced current?

SimbolSymbol

AktivitiActivity

J GegelungditarikkeatasThe coil is pulled upwards

K GegelungdiputarkanmenegakpadapaksimenegakThe coil is rotated about the vertical axis (a)

L Gegelung diputarkan supaya gegelung menjadimenegakThe coil is rotated so that the coil becomes vertical

A JdanKsahaja/J and K onlyB KdanLsahaja/K and L onlyC J,KdanL/J, K and L

Semuaaktivitididalamjadualmelibatkanperubahangarismedanmagnetmenyebabkangegelungmenghasilkanarusteraruh.All the activities in the table involve a change in the magnetic field lines linking a coil to produce an induced current.

MenggunakanpetuatangankananFlemingdidapatibahawaibujarimenunjukkankearahA.Using Fleming’s right-hand rule, it is found that the thumb points to the direction of A.





GegelungCoil



J

K

L

Q

PA B

CD

N S

KBAT




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Arusulang-alikdihasilkanapabilamagnetdigerakkankedalamdarikeluardarisolenoid.An alternating current is produced when the magnet is moved into and out of the solenoid.

Arusulang-alikdihasilkanapabilamagnetdigerakkankedalamdankeluardarisolenoid.Getaranakanberhentipadaakhirnya.An alternating current is produced when the magnet is moved into and out of the solenoid. The vibration will eventually stop.

4 Rajahmenunjukkangalvanomterberpusatsifaryangsensitifdisambungkankepadasolenoid.The diagram shows a sensitive zero-centre galvanometer connected to a solenoid.

Apakah yang berlaku pada penunjuk galvanometer apabila magnet

digerakkankeatasdankebawahdidalamsolenoiditu?What happens to the pointer of the galvanometer when the magnet is moved up and down into the solenoid?A Tidakdipengaruhi./Unaffected.B Terpesongkekiri./Deflects to the left.C Terpesongkekanan./Deflects to the right.D Terpesongkekiridankemudiankekanan. Deflects to the left and then to the right.

5 Rajahmenunjukkanmagnet bar yang tergantung pada spring.Magnetdisesarkandandibiarbergetardalamsolenoidpadaarahkeatasdankebawah.The diagram shows a bar magnet hung from a spring. The magnet is displaced and then left to vibrate in and out of the solenoid.

Antaragrafarus,Ilawanmasa,,yangmanakahmenunjukkanarusteraruhmengalirmelaluisolenoid?Which of the following graphs of current, I, against time, t, shows the induced current flowing through the solenoid?

A C

B D

Spring/Spring





I

0

0

0

0

I

I

I

t

t

t

t

Solenoid

KBAT




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Jenis arusType of current

Arus terusDirect current

Arus ulang-alikAlternating current

SimbolSymbol

Sumbera.t.d.c. source

Sumbera.u.a.c. source

GrafGraph

ArusdaripenjanaarusterusCurrent from d.c. generator

ArusdaribateriCurrent from battery

I/A

IO

–IO

t/sT 2T

I/A

t/s

I/A

t/s

0

0

0

6 Konduktorlurusyangpanjangdiletakkanantaraduamagnetkekalsepertiyangditunjukkandalamrajahdibawah.A long straight conductor is placed in between two permanent magnets as shown in the diagram below.

Antara berikut, yangmanakahmenghasilkan pesongan penunjuk yangterbesarolehGalvanometerberpusatsifar?Which of the following actions will produce the greatest deflection of the pointer in the galvanometer?

Arah gerakan konduktorDirection of movement of the conductor

Kelajuan gerakan konduktorSpeed of movement of the conductor

A Keatas/Upwards Perlahan/Slow

B Kebawah/Downwards Pantas/Fast

C Kebawah/Downwards Perlahan/Slow

D Ketepi/Sideway Pantas/Fast

Menggerakkandenganpantaswayarlurusmelintasimedanmagnetantaraduamagnetrata,arusteraruhdalamkonduktorlurusyangmenyebabkanpesonganterbesarolehgalvanometer.Moving a straight wire quickly across a magnetic field between two flat magnets, the current is induced in the straight conductor that causes the greatest deflection of the galvanometer.

KonduktorlurusStraight conductor

WayarpenyambungConnecting wire

GalvanometerberpusatsifarZero-centre galvanometer

Penyelesaian/ SolutionJawapanB/Answer B


Perbandingan antara Arus Terus dan Arus Ulang-alikComparison between Direct Current and an Alternating Current




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TransformerTransformer

Ialahalatyangdigunakanuntuk meningkatkan atau

menurunkan bezakeupayaan bekalanarusulang-alik berdasarkanprinsiparuhanelektromagnet.

Is an electrical device which increases or decreases an alternating voltage based on the principle of electromagnetic

induction.

1 Rajahmenunjukkanarusulang-alikdimanamagnitudberubahdenganmasa.The diagram shows an alternating current with a magnitude that changes with time.

(a) Apakaharuspuncak?/What is the peak current?(b) Apakahtempoharusulang-alik?/What is the period of the alternating current?(c) Apakahfrekuensiarusulang-alik?/What is the frequency of the alternating current?

Penyelesaian/Solution

(a) 5A(daripadagraf/from the graph)

(b) 0.04s(daripadagraf/from the graph)

(c) f=1———

0.04s=25Hz

t/s

I/A

5.0

0

–5.0

0.02 0.04 0.06 0.08 0.10

Ciri-ciriCharacteristics

(a) Arusyangmengalirhanyadalam satuarah .

A current that flows in only one direction .

(b) Arusterus bolehmengalirmelalui

perintang tetapitidakbolehmengalir

melalui kapasitor ./A direct current

can flow through a resistor but cannot flow

through a capasitor . (c) Magnitudarusberubahdenganmasa(arusdari

penjanaarusterus)./Magnitude of current changes with time (current from d.c. generator).

(d) Magnitudarus tidakberubah(arusdari

bateri)./ Magnitude of current does not change (current from battery).

(a) Arah arusdisongsangkanpadaselamasayangtetap./A current that reverses

its direction at fixed time intervals.

(b)Arusulang-alikbolehmengalirmelalui

kedua-dua perintang dan

kapasitor .

An alternating current can flow through both a resistor and a capacitor .

(c)Magnituddanaraharusulang-alik

berubah-ubah .

The magnitude and direction of an alternating

current changes .

Latihan / Exercise

Menganalisis Transformer Analysing Transformers

3.4




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Nota / Note:• Frekuensibezakeupayaansekunder,V

s,adalahsama

denganfrekuensibezakeupayaanprimer,V

p.

The frequency of the secondary voltage, V

s is the same as that of

the primary voltage, Vp.

• Magnitudbezakeupayaansekunder,V

sbergantung

kepadakadarbilanganlilitangegelungprimerdansekunder.The magnitude of the secondary voltage, V

s depends on the ratio

of the number of turns of the primary and secondary coils.

240V 24V

GegelungprimerPrimary coil

GegelungsekunderSecondary coil

StrukturStructure

` Terdiridaripadaduagegelungwayaryangdililitkanberasingan

pada terasbesilembut berlapis.Consists of two coils of wire wound round separately on a laminated

soft-iron core .` Gegelungyangdisambungkankepadavoltaninputdinamakan

gegelungprimer ./The coil connected to the input voltage

is called the primary coil .` Gegelungyangdisambungkankepadavoltanoutputdinamakan

gegelungsekunder .

The coil connected to the output voltage is called the secondary coil .

SimbolSymbol

PrinsipkerjaWorking principle

• Transformerbekerjaberdasarkanprinsiparuhanelektromagnet.A transformer works on the principle of electromagnetic induction.

• Apabilabezakeupayaanulang-alik,Vp,dibekalkanke

gegelungprimer , arusulang-alik mengalirmelaluigegelung.

When an a.c. voltage, Vp , is applied to the primary coil of the

transformer, an alternating current flows through the coil.

• Terasbesilembut dimagnetkan .

The soft-iron core is magnetised .

• Arusulang-alikmempunyai arah dan magnitud yangberubah.Olehitu,terdapatperubahanarahdanmagnitud

medanmagnet .

An alternating current has varying directions and magnitudes .

So there is a change in the direction and magnitude of magnetic field .

• Terasbesilembutmembekalkan medanmagnet yang

berubah-ubaharahdanmagnituddalamgegelung sekunder .

The soft-iron core provides a varying magnetic field in the

secondary coil.

• Medanmagnet yangberubah-ubahjugawujuddalamgegelungsekunder.

A varying magnetic field also occurs in the secondary coil.• Medanmagnetyangberubah-ubahakanmenghasilkan

arusaruhan dan d.g.eulang-alikteraruh,Vs, dalamgegelungsekunder.

The varying magnetic field will produce an induced current and alternating voltage, Vs in the secondary coil.




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Ciri-ciriCharacteristics

Kuasa / Power Dalamtransformerunggul,tiada tenaga yanghilangsemasaprosespemindahanbezakeupayaan.

In an ideal transformer, there is no energy loss during the process of transforming the voltage.

Olehitu, kuasaoutput=kuasainput

Hence, output power = input power

IsVs=IpVp

Dimana/where,

Is=Arussekunder/Secondary current

Ip=Arusprimer/Primary current

Vs=Bezakeupayaansekunder/

Vp=Bezakeupayaanprimer/Primary potential difference

Kecekapan / EfficiencyDalamtransformersebenar,sebahagiantenagaakanhilangakibatdari:In real transformers, some energy will be lost. This is due to:

(a) kesanpemanasandalamgegelungdawai heating effect in the coils

(b) kesanaruspusaryangteraruhdalamterasbesi eddy currents which are induced in the iron core

(c) memagnetkandanmenyahmagnetkanterasbesi magnetisation and demagnetisation of iron core

(d) kebocorangarismedanmagnet(fluksmagnet) leakage of magnetic field lines (magnetic flux leakage)

Efficiency = Output powerInput power × 100%

Kecekapan= KuasaoutputKuasaInput

×100%

RumusFormula

Ns

Np

= V s

Vp

Dimana/where

Ns=Bilanganlilitangegelungsekunder

Ns=No. of turns in the secondary coil

Np=Bilanganlilitangegelungprimer

Np=No. of turns in the primary coil

Nota/Note:Mengapakahtransformertidakbolehberfungsidenganbekalankuasaarusterus?Why does the transformer not work with a d.c. power supply?

• Jikabezakeupayaanarusterusdigunakanpadagegelungprimer,bezakeupayanoutputpadagegelungsekunderakanmenjadisifar.If d.c. voltage is applied to the primary coil of the transformer, the output voltage at the secondary coil will be zero.

• Iniadalahkeranabekalankuasaarusterusmembekalkanarusmantapdalamgegelungprimerdimanaiamempunyaimagnitudtetapdanarahyangtetap.This is because a d.c. power supply gives a constant current in primary coil which has constant magnitude and direction.

• Olehitu,medanmagnetyangdihasilkandidalamterasbesilembutmempunyaimagnituddanarahyangtetap.So the magnetic field produced in the soft iron core has constant magnitude and direction.

• Terasbesilembuttidakmembentukgarismedanmagnetberubah-ubahdidalamgegelungsekunder.The magnet does not create a changing magnetic flux in the secondary coil.




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Jenis transformerType of transformers

Transformer injak naikStep-up transformer

Lukiskanrajahtransformerinjaknaik.Draw the diagram of a step-up transformer.

(a) Transformerinimenghasilkanbezakeupayaanoutput,V

s

yang lebihtinggi daripadabezakeupayaaninput,V

p(menaikkanbeza

keupayaan),This transformer produces an output voltage, V

s , which is

higher than the input voltage, V

p ,

iaitu/i.e. Vs>V

p

(b) Bilanganlilitandalamgegelungsekunder

lebihbesar daripadabilanganlilitangegelungprimer.

The number of turns in the secondary coil is

bigger than the number of turns in the primary coil.

iaitu/i.e. Ns>N

p

Transformer injak turunStep-down transformer

Lukiskanrajahtransformerinjakturun.Draw the diagram of a step-down transformer.

(a) Transformerinimenghasilkanbezakeupayaanoutput,V

s

yang lebihrendah daripadabezakeupayaaninputV

p(menurunkanbeza

keupayaan),This transformer produces an output voltage, V

s , which is

lower than the input voltage, V

p ,

iaitu/i.e. Vs<V

p

(b) Bilanganlilitandalamgegelungsekunder

lebihkecil daripadabilanganlilitangegelungprimer.The number of turns in the

secondary coil is smaller than the number of turns in the primary coil.

iaitu/i.e. Ns<N

p

Vs

Vp





Vs

Vp




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Diberi/ GivenNs=250lilitan/turns,N

p=50lilitan/turns,V

p=12V

Ns

Np

=Vs

Vp

Vs= NsVp

Np

=250lilitan/turns×12V

50lilitan/turns=60V

1 Bilanganlilitandalamgegelungprimerdangegelungsekunderpadatransfomermasing-masingialah50dan250.Apakahbezakeupayaanoutputapabilatransformermenggunakanbekalankuasa12V?The number of turns in the primary and secondary coil of a transformer are 50 and 250 respectively. What is the output voltage when the transformer is using a voltage of 12 V?Penyelesaian/Solution

Sebab kehilangan tenagaCauses of energy losses

Cara mengurangkan kehilangan tenagaWays to minimise energy losses

1 Rintangangegelung TenagahilangsebagaihabadidalamgegelungkeranaE=I2Rt

Resistance of coil Energy is lost as heat in the coil because E = I 2Rt

1 Wayarkuprumtebal digunakan

untukmengurangkanrintangangegelung.Thick copper wire is used to reduce

the resistance of the coil.

2 Aruspusar dalamterasbesiMedanmagnetberubah-ubahmenyebabkanelektrondalamterasbesilembutberputarmembentukaruspusar(aruseddy).Aruseddymenyebabkanpemanasandidalamterasdanmenyebabkankehilangankuasa.

Eddy currents in the iron core

The changing magnetic field causes the electrons in the soft iron core to circulate around as eddy current. The eddy current produces heat in the core and causes loss of power.

2 Terasbesiberlamina(berlapis-lapis) digunakanuntukmenambahkanrintangandanmengurangkanpengaliranaruspusar.

Laminated iron core is used to increase the resistance and decrease the flow of eddy currents.

3 Kehilanganhisterisis Kehilangantenagauntukmemagnetkandanmenyahmagnetkanterasdenganmenggunakanarusulang-alikdidalamgegelungprimer.Tenagahabadibebaskan. The hysterisis loss

The loss of energy due to magnetising and demagnetising the core by the alternating current in the primary coil. This produces heat energy.

3 Menggunakan terasbesilembut keranaterasbesilembutbolehdimagnetkandandinyahmagnetkandenganmudah.

Soft iron core can be magnetised and demagnetised easily. So the core requires small amount energy to be magnitised and demagnitised.

4 Kebocoranflukmagnet Tenagaelektikhilangapabilasebahagiankecildaripadafluksmagnetyangdihasilkanolehgegelungprimeryangterasingdengangegelungsekundermenyebabkand.g.e.teraruhdalamgegelungsekunderberkurang.

Leakage of magnetic flux Electrical energy is lost when a fraction of the magnetic flux produced by

the primary coil does not link with the secondary coil.

4 Melilitkan gegelungsekunderdiatasgegelungprimersecararapatdanbertindih.

Winding the secondary and primary coils on top of each other.

Faktor yang mempengaruhi kecekapan transformer dan cara untuk meningkatkan kecekapannya (mengurangkan tenaga yang hilang)Factors that affect the efficiency of a transformer and ways to improve the efficiency (minimise energy losses of a transformer)

Latihan / Exercise




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Diberi/ GivenVs=12V,V

p=240V,

Np=500lilitan/turns

Ns

Np

= Vs

Vp

Ns

500lilitan/turns= 12V

240V

Ns=

12V×500lilitan/turns240V

=25lilitan/turns

2 Rajahmenunjukkan12V,36Wmentolmenyaladengankecerahannormalapabiladisambungkankepadabekalankuasa240Vmelaluitransformer.Bilanganlilitangegelungprimerialah500.The diagram shows a 12 V, 36 W bulb light up with normal brightness when it is connected to a 240 V mains supply through a transformer. The number of turns of the primary coil is 500.

Berapakahbilanganlilitangegelungsekunder?What is the number of turns of the secondary coil?Penyelesaian/Solution

Diberi/ GivenVp=240V,P

output=90W,V

s=30V

(a) Poutput

=IsV

s

90W =Is×30V

Is = 90W

30V I

s =3A

3 Transformerinjak-turundisambungkankebekalankuasa240Vdanmemberikankuasa90Wkepadakomputerriba,30V.

[Andaikantransformeradalahunggul.]A step-down transformer connected to 240 V mains power supply delivers 90 W of power at 30 V to a notebook computer. [Assume that the transformer is ideal.]

Hitungkan/Calculate(a) arusdalamgegelungsekunder. the current in the secondary circuit. (b) arusdalamgegelungprimer. the current in the primary coil.Penyelesaian/Solution

240V 12V,36W

4 Rajahmenunjukkan12V,48Wmentolmenyaladengankecerahannormalapabiladisambungkankepadabekalankuasa240Vmelaluitransformer.The diagram shows a 12 V, 48 W bulb light up with normal brightness when it is connected to a 240 V mains supply through a transformer.

Hitungkan/Calculate(a) bilanganlilitangegelungprimer. the number of turns of the primary coil.(b) arusdalamgegelungsekunder. the current in the secondary coil.(c) kecekapantransformer. the efficiency of the transformer.Penyelesaian/Solution

Diberi/ GivenVp=240V,N

s=200lilitan/turns,

Vs=12V,I

p=0.3A

(a) Ns

Np

= Vs

Vp

200lilitan/turnsNp

= 12V240V

Np=

240V×200lilitan/turns12V

Np=4000lilitan/turns

(b) Vs=12V,P

s=48W

\ Is= Ps

Vs=

48W12V

=4.0A

(c) Kuasaoutput/ Output power=48W

Kecekapan/Efficiency=P

output

Pinput

×100%

= 48WIpVp

×100%

= 48W0.3A×240V

×100%

=66.67%

12V,48W

0.3A

Ns=200

240V

(b) IpV

p =I

sV

s

Ip×240=3A×30V

Ip = 90W

240V =0.375A

Kuasainput=Kuasaoutput/ Input power = Output powerJadi,/ Therefore, I

pV

p=90W

\ Ip=

90W240V

Ip=0.375A

atau

KBAT




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Pelbagaikaedahpenghasilantenagaelektrikdankesankepadapersekitaran(kebaikandankeburukan)Various ways of generating electricity and their effects on the environment (advantages and disadvantages)

JenisType

KebaikanAdvantages

KeburukanDisadvantages

1 Stesen janakuasa terma / Thermal power stations

(a) Bahanapiseperti arangbatu,petroleum,gasasli

dan uranium digunakandalamstesenjanakuasaterma.

Fuels such as coal, petroleum, natural gas and uranium are used in the thermal power stations.

(b) Tenagahaba dihasilkanolehpembakaranarangbatuatauminyakdalamrelauataudaripembelahannukleusuraniumdalamterasreaktornuklear.

Heat energy is produced by burning coal or oil in a furnace or from the fission of uranium nuclei in the core of a nuclear reactor.

(c) Airmenyeraptenagahabadidalamrelauataupenukarhabadanbertukarmenjadi

stim pada tekanantinggi . Water absorbs the heat energy in a boiler or heat-

exchanger and is changed into steam at a high pressure .

(d) Stimbertekanantinggimenukarkantenagahaba

kepada tenagamekanikal apabilaiamemutarkanturbin.

The high-pressure steam converts heat energy into mechanical energy as it turns the turbine.

(e) Generatormenukarkantenagamekanikalkepada

tenagaelektrik . The generator converts the mechanical energy into

electrical energy .(f) Kecekapan:30%–35%tenagayangdisimpandi

dalambahanapiditukarkankepadatenagaelektrik. Efficiency: 30% – 35% of the energy stored in the fuel is

transformed into electrical energy.

(i) Bolehmembangunkansebuahbandarbaru(menggunakanarangbatu,petroleum)

Can develop a new town (using coal, petroleum)

(ii) Bahanbuanganbolehdikitarsemula(biojisim)

Can recycle the waste matter (biomass)

(iii)Memerlukanbahanradioaktifyangkecil

Small amount of radioactive is required

(i) Pencemaranudara : Pembakaranbahanapi

menghasilkanasap,habukdanasidtoksikdiudara.

Air pollution : Burning of fuels produces smoke, dust and toxic acid in the air.

(ii) Hujanasid :Pembakaranbahanapijugamenghasilkangasberasidsepertisulfurdioksidadannitrogenoksida.Gasinilarutdalamairdalamatmosferauntukmembentukasidyangmenyebabkanhujanasid.

Acid rain : Burning of fuels also produce acidic gases such as sulphur dioxide and nitrogen oxides. These gases dissolve in water in the atmosphere to form acids which results in acid rain.

(iii) Kesanrumahhijau :karbondioksidaberlebihandiatmosferamenyebabkansuhuyanglebihtinggiterhasildipersekitaran.

Greenhouse effect : The excessive carbon dioxide in the atmosphere raises the temperature in the environment.

(iv) Tidakbolehdiperbaharui :bekalanterhaddanbolehhabis.

Non-renewable : Their supply is limited and they will

eventually run out.

(v) Mahal/Expensive .

(vi) Kesansinaranradioaktif yangmerbahayakepadamanusiadanpersekitaran.

Harmful effects of radioactive

radiation on humans and environment.

(vii) Berbaubusuk :Satubaubusukdilepaskandaripadabiomass.

Bad odour (smell) : A bad odour is released from the biomass.

RotorRotor

Stator coilsTurbinesFurnace

Relau bagas

TurbinGegelung pemangun

PendandangBoiler

Pam Stim tekanan rendah dari turbin

Pump

PamPump

High pressuresteam at 800oC

Stim bertekanan tinggi pada 800oC

Hot waste gasesGas buangan panas

Wap air panas

Talian penghantaranTransmission lines

Hot water vapour

Low pressuresteam from turbines

PenjanaGenerator

Air penyejuk daripada sungai atau lautCooling water from river or sea

Air penyejuk dibuang semula ke sungai atau lautCooling water discharged back into river or sea

Transformer injak naikStep-up transformer

Memahami Penjanaan dan Penghantaran Tenaga Elektrik Understanding the Generation and Transmission of Electricity

3.5




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JenisType

KebaikanAdvantages


2 Stesen kuasa hidroelektrik/Hydroelectric power station

(a) Stesenhidroelektriktidakperlumemanaskanstim. In hydroelectric stations, there is no need to heat steam at all.(b) Airdikumpuldalamtakungan(empangan)yangtinggidan

mempunyai tenagakeupayaangravitiyangtinggi . Water is collected in a high reservoir and possesses

high gravitational potential energy .(c) Apabilaairitumengalirmelaluipaip,tenagakeupayaan

gravitiinibertukarkepada tenagakinetik . When the water flows through a pipe, its gravitational potential energy

is changed to kinetic energy .(d) Tenagakinetikditukarkepadatenagaelektriksemasaair

yangmengalirmemutarkanbilahturbin. The kinetic energy of water is changed to electrical energy when the

water turns the blades of a turbine.

(i) Bersihdantidakmembebaskanbahancemarkepersekitaran.

Clean and does not emit pollutants to the environment.

(ii) Bolehdiperbaharui.

Renewable.(iii)Boleh

membangunkankawasanrekreasi.

Can develop a recreation area.

(iv)Mengawalbanjir. Control flood.

(i) Mengganggukeseimbangan

ekosistem dipersekitaran.Satukawasanhutanyangbesarperludimusnahkantermasukfloradanfauna.

Disturbs the equilibrium of the ecosystem

in the environment. A large area of forest land has to be destroyed, including flora and fauna.

(ii) Mengancam/menyesarkan

penduduk tempatan

Threatens / Displaces localpopulation .

(iii)Perbelanjaantinggi

High cost

3 Tenaga solar boleh berubah kepada tenaga elektrik melalui dua kaedah:

Solar energy can be converted into electrical energy by two methods:(i) Relausuria/Solar furnace

(a) Pemantulparabolacekungdigunakanuntuk

memfokus dan menumpukantenagahaba darimatahari.

A concave paraboloidal reflector can be used to focus and concentrate the radiant

heat energy from the sun. (b) Tenagahabadigunakanuntukmenghasilkan

stim yangmempunyai tenaga

kinetik dandigunakanuntukmemutarkanturbinbagipenjanaelektrik.

The heat energy is used to produce steam . The

high kinetic energy of this steam is used to drive the turbine of an electrical generator.




Renewable.(iii)Percuma. Free.

(i) Memerlukan ruang

yangbesar untukmengumpulkancahayamatahari.

Requires a large area to collect the Sun’s rays.

(ii) Kecekapanpenukaran

adalahagak rendah (kira-kira5%)danhargauntukmenghasilkansel

solaragak mahal . The efficiency of conversion

is quite low (about 5%) and the solar cells are

expensive to produce.

(iii) Keamatan sinaranmatahariyang

dikumpulkantidak

konsisten ,daninibergantungkepadacuacadanmasa.

The intensity of Sun’s rays collected is not

consistent as this depends on the weather conditions and the time of day.

Dam

Water

Transmission lines Stored water

Generator

Turbines

Empangan

Air

Talian penghantaran Air simpanan

Penjana

Turbin

Focal point

Sunlight

Concave paraboloidal reflector

Titik fokus

Cahaya matahari

Pemantul paraboloid cekung

Turbin anginWind turbine

Sunlight

InsulationPenebat

PamAir sejuk masukCold water in

Pump

To domestic hot water systemKe sistem pemanas air

Transparent coverPenutup transkparensi

Panel penyerapAbsorbing panel

Sinar matahari

Output

Metal contact

N-type silicon P-type silicon

Metal grid contact

Glass coverPenutup kaca

Output

Sentuhan logam

Silikon jenis-N Silikon jenis-P

Sesentuh grid logam

SunlightSinar matahari




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JenisType

KebaikanAdvantages


(c) Panelsolarmenggunakantenagamatahariuntuk

menjana tenagaterma untukmemanaskanairdirumah.

Solar panels use sun energy to generate thermal energy to heat water at home.

(ii) Selsolar/Solar cell

(a) Selsolardiperbuatdaripadabahansemikonduktoryang

manamengaruhkan d.g.e. apabilaterdedahkepadacahayamatahari.

Solar cells are made of semiconductor materials which develop

an e.m.f. when exposed to sunlight. (b) Selsolardigunakandalamkalkulator,lampu,jam

tangan,pemanasairdansatelit. Solar cells are used in calculators, lamps, wrist watches, water

heaters and in satellites.

4 Tenaga angin / Wind energy

Tenagakinetik anginmemutarkanbilahyangdihubungkankepadapemutarpenjanaelektrikuntuk

menghasilkan tenagaelektrik .

The kinetic energy of wind rotates blades connected to the rotor

of an electrical generator to produce the electrical energy .

(i) Bersih dantidakmembebaskanbahancemarkepersekitaran.


(ii)Boleh

diperbaharui

Renewable

(iii) Percuma

Free

(i) Memerlukan

kawasanluas untukmembinaturbinangin.

Requires a large area to construct a wind turbine.

(ii) Kelajuanputaranpemutarturbin

tidakkonsisten ,bergantungkepadakeadaan.

The speed of rotation of the rotor is

not consistent , depending on weather conditions.

(iii)Membebaskan

bunyibising .

Produces noise .

Focal point

Sunlight


Titik fokus

Cahaya matahari



Sunlight

InsulationPenebat


Pump




Sinar matahari

Output

Metal contact


Metal grid contact


Output

Sentuhan logam


Sesentuh grid logam


Focal point

Sunlight


Titik fokus

Cahaya matahari



Sunlight

InsulationPenebat


Pump




Sinar matahari

Output

Metal contact


Metal grid contact


Output

Sentuhan logam


Sesentuh grid logam


Sunlight

InsulationPenebat


Pump


Transparent coverPenutup transparensi

Permukaan penyerap haba hitamBlack heat-absorbing surface

Sinar matahari




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JenisType

KebaikanAdvantages


5 Tenaga ombak / Wave energy

‘Salterduck’ialahbentukkhasyangterapungdanbergolekkedepandankebelakangapabilaombakmenghentamkeatasnya.Gerakanberombakbolehdigunakanuntukmemacuturbindan

menjanaaruselektrik .Kesemuapenjanatenagamempunyaibarisan'salterduck'yanglurusmenghadapombakyangdatang.The ‘Salter duck’, is a specially shaped float which rocks back and forth as the waves strikes it. This rocking motion can be used to

drive a turbine and generates electricity . The whole wave energy generator has a row of ducks lined up facing the on coming waves.




Renewable.(iii)Percuma. Free.

(i) Memerlukankos tinggi untukmembinadanmengekalkangeneratorgelombang.

Needs high cost to build and maintain the wave generators.

(ii) Sangatmudahrosakdan

susah dipertahan. Very vulnerable and

difficult to protect from damage.

BoomBalancing float

Gerakan berombak

Ombak

Permukaan ledakan Keseimbangan apungan

Rocking motion

Waves

(i) Tenagaelektrikdihantarpada bezakeupayaanyangtinggi danmenggunakanarusulang-alik.

Electrical energy is transmitted at a high voltage and uses an alternating current.

(ii) Transformerinjaknaikyang menaikkan bezakeupayaanpadavoltanlampautinggiiaitu110000Vatau 132 000 V. Beza keupayaan yang ditingkatkan akan menyebabkan penghantaran kuasa dengan

aruskecil .

A step-up transformer which increases the voltage to as high a voltage as 110 000 V or 132 000 V. The high voltage

will cause the power to be transmitted with a small current .

(iii)Transformer injak turundigunakanuntuk menurunkan bezakeupayaansebelumdihantarkepadapengguna.

Step-down transformers are used to lower the voltage before delivering to the consumers.

Penghantaran Tenaga ElektrikTransmission of Electricity




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Tenaga yang hilang dalam kabel penghantaran tenaga elektrik dan

kelebihan penghantaran voltan tinggiThe energy loss in electricity transmission

cables and the advantage of high voltage transmission

Sistem Rangkaian Grid NasionalThe National Grid network

Isu PenghantaranTransmission Issues

(i) Kesanpemanasanyang

disebabkanoleh rintangan kabelmenyebabkankehilangantenagaelektriksebagai

tenagahaba .

The heating effect due to the resistance of the cable causes loss of

electrical energy as heat energy .(ii) Apabilaarusmengalirdalam

kabel,kehilangankuasa,P,melaluipemanasanadalah:

When a current flows in a cable, the power loss, P, through heating is:

P=I2R

(iii) Kuasayanghilangbolehdikurangkandengan:

The power loss can be reduced by:

(a) mengurangkanrintangan

kabel

reducing the resistance of the cables

(b) mengurangkanarus

mengalirdalamkabel

reducing the current in the cables

(iv) Olehitu,untukmengurangkan

rintangankabel, wayarkabel

tebal digunakan,

contoh:wayarkuprumataualuminium

In order to reduce resistance of the

cables, a thick cable is used e.g copper or aluminium.

(v) Kuasayangdihantarmelaluikabel

ialah P=IV . The power transmitted by the cables is

P = I V .(vi) Maka,arus,I,yangmengalir

melaluikabel: So, the current, I, flows in the cables:

I= PV

(vii)Inibermaksud,arus,Iyangmengalirmelaluikabeladalah

berkadarsongsang denganbezakeupayaan.This means that the current in the cables

is inversely proportional to the voltage.

• RangkaianGridNasionalmerupakansatu

sistemrangkaiankabel voltanlampau

tinggi dalamsaturangkaiantertutupmenghubungkansemuastesenkuasautamadinegarainidengansemuapenggunautamasepertirumah,pejabat,bandar-bandardankilang-kilang.The National Grid Network is a network system of

extra high voltage cable transmission lines which connects all the major power stations in the country with all the major users such as our homes, offices, cities and factories.

• Tenagaelektrik dijanakandistesenkuasadimanabezakeupayaanditingkatkandenganmenggunakan

transformerinjaknaik untukmengurangkanarusyangmengalirmelalui

grid.Inimengurangkan kehilangankuasa dalamkabelsemasapenghantaran.

Electrical energy is generated in power stations where its voltage is increased by

using a step-up transformer to reduce

the power loss in the cables during transmission by lowering the current flowing through the grid.

• Disubstesen,sebelumpenghantaran

kepadapelbagaipengguna, voltan

lampautinggi dikurangkan

denganmenggunakan transformar

injakturun .At sub-stations, before reaching the various

consumers, the high voltage is reduced by

using step-down transformers .

• PenghantaranmelaluibawahtanahataudiatastanahOverhead or underground

(i) Kabelvoltanlampau

tinggi adalahcarayanglebihmurahuntukmenghantarkuasapadajarakyangjauh.

Extra high voltage cables is the cheapest way of sending power over long distances.

(ii) Untukmengelakkanpercikanelektrik,carayangberkesanialah

menyalut penebatpadakabeluntukmemastikanruangudarayangbesardisekelilingmereka.

To prevent sparkling, the effective way is to

insulate the cables to keep huge air space around them.

(iii) Kabelperludigantungpadatiang.

The cables have to be suspended from pylons.

• KoskabelCost of cables

(i) Kabel kuprum

mempunyai rintangan

rendah tetapikosyangtinggi.

Copper cables

have low

resistance but high cost.

(ii) Kabel aluminium seringdigunakankeranaiaringan,

rintangannyarendah dankosnyalebihrendah.

Aluminium cables are usually used as they are light, have

low resistance and

its cost is low .

Supergrid (275 kV /400 kV)

Grid (132 kV)

Power station 25 kV

Transformer (275 kV/400 kV /132 kV)

Heavy industry (33 kV) Towns, villages and farms

(415 V/240 V)

Light industry(11 kV)

Transformer (132 kV/ 33 kV)

Transformer (11 kV/415 V/240 V)

Transformer (33 kV/ 11 kV)

Transformer (25 kV/275 kV /400 kV)

Kuasa stesen

Industri berat Industri ringan Bandar, kampung dan ladang




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Kebaikan Sistem Rangkaian Grid NasionalAdvantages of the National Grid Network System

1 Mudahdikendalikan Penjanaantenagaelektrikbolehdikawaldandilaraskanmengikutkeperluanpadamasa-masatertentu.

Easy to manage

Regional control and switching centres enable power to be sent where and when it is needed.

2 Pembekalantenagaelektrikberterusan

tanpagangguan Apabilakawalanserantaudanpusatpensuisanmembenarkanbeberapastesendalamrangkaiantertutupmemutuskanrangkaiannyauntukkerja-kerjapenyelenggaraan,penggunamasihdapatbekalantenagadaripadabekalanpenjanalain.

Continuous supply of electricity

While regional control and switching centres allow some stations and lines to be shut down for maintenance work, consumers still get energy supply from other generator supplies.

3 Mengurangkankospenjanaan Penghantaranvoltanlampautinggibolehmengurangkankuasayanghilangdalamkabelpenghantaran.Kospenghasilanelektrikdapatdikurangkan.

Reducing cost of generation

High voltage transmission can reduce the power loss in transmission cables. The cost of production is reduced.

4 Mudahuntukdikawaldandiselenggara Semasapenggunaantenagaelektrikyangtinggi,lebihbanyakpenjanabolehdihidupkan.Tetapisemasapermintaanpenggunakurang,sebahagianpenjanabolehdipadamkan.

Easy to control and regulate

At peak periods of electricity usage, more generators can be switched on. During periods of low demand, some generators can be turned off.

• KebocorancasantarakabeldenganbumiCharge leakage between the cables and the earth(i) Untukmengelakkebocoran

cas,kabel aluminium elektrikdisokongolehmenarakawatyangtinggi.To prevent charge leakage, the

aluminium cables are supported by high metal pylons.

• MerbahayajikadisambarpetirDanger of being struck by lightning(i) Kabelditebatdengan

porselin dankacasupayakabeltersebuttidakbersentuhandenganmenarakawatelektrik.The cables are properly fixed

with porcelain and glass support so that the cables do not touch the pylons.

• MerbahayajikadilanggarolehpesawatringanDanger of being struck by light aircraft(i) Lampudanpenandakhas

mestidipasangpadamenarakawatelektrikitu.Lights and special markers must be attached to the pylons.




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(a) Hitungkannilaiarusdalamkabel,I Calculate value of current in the cable, I

Kuasayangdihantarolehkabel,P=IV The power transmitted by the cable, P = IV

80×106W=I×(80×103V)

I=80×106W80×103V

=1000A

Olehitu,kuasahilangakibatrintangan, So, the power loss due to the resistance P=I 2R =(1000A)2×5Ω =5×106W

(b) Peratuskuasahilang Percentage of power loss

=5×106W80×106W × 100%

=6.25%

(c) Tenagadihantar=Kuasadibekal–Kuasahilang Power transmitted = Power supply – Power loss =80×106W–5×106W =75×106W

Kecekapan/So, efficiency=75×106W80×106W ×100%

=93.75%

(d) Penguranganvoltan/Voltage drop=IR =1000A×5Ω =5000V

2 Stesenkuasamenjana80MWkuasaelektrikpadabezakeupayaan80kVa.u.melaluirintangankabel5Ω.A power station generates 80 MW of electric power at a voltage 80 kV through a cable of resistance 5 Ω. Determine:(a) kuasayanghilangsemasapenghantarantenagamelaluikabel.

the power loss in the transmission cable. (b) peratuskuasayanghilang./the percentage of the power loss.(c) kecekapanpenghantarankuasa./the efficiency of the power transmission.(d) penguranganbezakeupayaandidalamkabel./the voltage drop in the cable.Penyelesaian/Solution

1 Stesen kuasamenjana 40 kW kuasa elektrikmenggunakan rangkaian penghantaran tenaga berintangan8Ω.BerapakahkehilangankuasasemasapenghantaranakibatrintangankabeljikatenagaelektrikdihantarpadaA power station generates 40 kW of electric power using a power transmission line with resistance of 8 Ω. What is the power wasted due to the resistance of the transmission cables when the current is transmitted at(a) 5000V (b)20kVPenyelesaian/Solution

(a) Hitungkannilaiarusdalamkabel,I Calculate value of current in the cable, I

Kuasadihantarmelaluikabel,P=IV The power transmitted by the cable, P = I V 40×103W=I×5000V

I=40×103W

5000V

=8A

Maka,kuasayanghilangdisebabkanrintangan, So, the power loss due to the resistance, P=I 2R =(8A)2×8Ω =512W

(b) P=IV 40×103W=I×(20×103)V

I=40×103W20×103V

=2A

Maka,kuasayanghilangdisebabkanrintangan, So, the power loss due to the resistance, P=I 2R =(2A)2×8Ω =32W

Latihan / Exercise

KBAT

KBAT




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1 Rajah 1 menunjukkan susunan radas untukmengkaji corak medan magnet yang terbentukapabilaaruselektrikmengalirdalamkonduktor.Diagram 1 shows an arrangement of apparatus to study the pattern of magnetic fields which are formed when the current flows through conductors.

6V 6V

KadbodCardboard

Rajah 1 / Diagram 1

Corak medan magnet yang manakah terbentukpadakadbodapabilakedua-duasuisdihidupkan?Which magnetic fields pattern is formed on the cardboard when both switches are closed?

A

B

C

D

2 Apabilasuisdalamlitardihidupkan,dawaiRakandipesongkan.When the switch is closed in the circuit, wire R deflects.

SuisSwitch

Merkuri/Mercury

PerintangResistor

RodlogamMetal rod

DawaiRWire R

Rajah 2 / Diagram 2

ArahpesonganitutidakbolehditentukandenganmenggunakanThe direction of the deflection cannot be determined by

A petuaTanganKananFleming Fleming’s right hand ruleB petuaTanganKiriFleming Fleming’s left hand ruleC petuaskrugabusMaxwell Maxwell’s corkscrew rule

3 Rajah 3 menunjukkan sebatang magnetbersebelahan dengan suatu gegelung. Petunjukgalvanometer terpesong semasa magnet ituditolakkedalamgegelung.Diagram 3 shows a coil of wire placed next to a magnet. The galvanometer pointer deflects when the magnet is pushed into the coil.

Rajah 3 / Diagram 3

Tindakan yang manakah akan menambahkanpesonganpetunjukgalvanometeritu?Which action will increase the deflection of the galvanometer pointer?

A Kutubmagnetitudisongsangkan The magnet pole is reversedB Bilanganlilitangegelungituditambah The number of coil is increasedC Gegelung dibuat daripada wayar yang

bertebat The coil is made from insulated wireD Magnet itu ditolak perlahan-lahan ke dalam

gegelung The magnet is pushed slowly into the coil

4 Rajah 4 menunjukkan magnet yang berayun didalamsatusolenoid.Diagram 4 shows a magnet oscillating in the solenoid.

Rajah 4 / Diagram 4

Tindakan yang manakah tidak menambahkanpesonganpetunjukgalvanometer?Which of these actions will not increase the deflection of the galvanometer pointer?

A Menukarkankekutubanmagnet Reversing the polarity of the magnetB Menambahbilanganlilitansolenoid Increasing the number of coils in the solenoidC Mengurangkandiametersolenoid Decreasing the diameter of the solenoidD Menambahkanlajuayunanmagnet Increasing the oscillation speed of the magnet

atihan Pengukuhan / Enrichment ExerciseL




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5 Rajah 5 menunjukkan struktur binaan motorelektrik.Diagram 5 shows the structure of an electric motor.

N S

Rajah 5 / Diagram 5

Corakmedanmagnetyangmanakahbetulapabilasuislampudihidupkan?Which of the magnetic field patterns is correct when the motor is switched on?

A

B

C

D

6 Rajah6menunjukkansebuahtransformerringkas.Diagram 6 shows a simple transformer.

Input240V

Output6V




Rajah 6 / Diagram 6

Arus dalam gegelung primer ialah 0.1 A dankecekapan transformer itu ialah 60%. KuasaoutputtransformerituialahThe current in the primary coil is 0.1 A and the efficiency of the transformer is 60%. The output power of the transformer is

A 6.0W C 24.0WB 14.4W D 40.0W

7 Rajah 7 menunjukkan satu bayang terbentukdi atas skrin Tiub Palang Maltese. Bayang itudipesongkanolehmagnet.Diagram 7 shows a shadow formed on the screen of a Maltese Cross Tube. The shadow is deflected by the magnets.

6.3Va.u.6.3 V a.c.

VLTEHT MagnetY

Magnet Y

MagnetXMagnet X

BayangpadaskrinShadow on screen

Rajah 7 / Diagram 7

BayangitudipesongkankeThe shadow is deflected towardsA magnetX magnet XB magnetY magnet YC bawah the bottomD atas/the top

8 Rajah 8 menunjukkan sebatang magnet yangdilepaskan dari satu ketinggian dan memasukisebuah gegelung yang disambung ke sebuahgalvanometer.Diagram 8 shows a magnet which is released from a height and enters a coil which is connected to a galvanometer.

MagnetMagnet

DawaiWire

GegelungCoil


Rajah 8 / Diagram 8

Sudut pesongan jarum galvanometer akanberkurangapabila

The angle of deflection of the pointer of the galvanometer decreases whenA kekutubanmagnetditerbalikkan. the polarity of the magnet is reversed.B magnet itu dilepaskan dari kedudukan yang

lebihrendah. the magnet is released from a lower position.C bilanganlilitanpadagegelungbertambah. the number of turns of the coil is increased.




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1 Rajah1.1menunjukkanarahpenunjukkompasXdengansuisdibuka.Diagram 1.1 shows the direction of the pointer of compass X with the switch opened.

SuisSwitch

KadbodCardboard

Kompas YCompass Y

Kompas XCompass X

Serbuk besiIron filings

Rajah 1.1 / Diagram 1.1

(a) PadaRajah1.2apabilasuisditutup, On Diagram 1.2, when the switch is closed,

(i) tandakandengananakpanaharaharusdidalamlitar. mark with arrows the direction of the current in the circuit.

(ii) lukiscorakmedanmagnetdiataskadbodtersebut. draw the magnetic field pattern on the cardboard.

(iii) tandakandengananakpanaharahpenunjukkompasY. mark with an arrow the direction of the pointer of compass Y


(b) NamakanpetuayangdigunakanuntukmenentukanarahmedanmagnetdalamRajah1.2. Name the rule used to determine the direction of the magnetic field in Diagram 1.2.

Petuagenggamantangankanan

Right hand grip rule

9 PenghantaranelektrikdisalurkanpadavoltanyangsangattinggisupayaElectricity is transmitted at a very high voltage in order toA meningkatanarusdalamkabel increase the current in the cablesB mengurangkanrintangankabel reduce the resistance of the cablesC mengurangkankehilangankuasa reduce power lossD menambahkanrintangankabel increase the resistance of the cables

10 Berapakah kehilangan kuasa dalam kabelpenghantaran apabila 50 kW dihantar melaluikabelyangberintangan4.0Ωpadavoltan10kV?What is the power loss in a transmission cable when 50 kW is transmitted through a cable with a resistance of 4.0 Ω at a voltage of 10 kV?

A 5WB 25WC 100WD 200W

oalan Struktur / Structure QuestionsS




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(c) Jadual1menunjukkan tiga rekabentukmotorelektrikarus terus,P,QdanR,yangdigunakanuntukmembinasebuahkipaskecil.

Table 1 shows three direct current electric motor designs, P, Q and R, used to build a small fan.

Motor / Motor Reka bentuk / Design

P NS

Bilah kapasFan blade

Bilangan lilitan gegelung = 50 lilitanNumber of turn of coil = 50 turns

BateriBattery

Magnet kekal berbentuk separa bulatanSemi circular-shaped permanent magnet

QN

S



BateriBattery


RN

S



BateriBattery


Jadual 1 / Table 1

BerdasarkanJadual1,nyatakanciri-cirisesuaisebuahmotorelektrikyangbolehmemutarkankipaspadakelajuanyangtinggi.Berikansebabuntukkesesuaianciri-ciriitu.

Based on Table 1, state the suitable characteristics of an electric motor to be used to turn the fan at a high speed. Give reasons for the suitability of the characteristics.

(i) Bilanganlilitangegelung.Sebab. Number of turns of the coil. Reason.

Lebihbanyaklilitan.Untukmeningkatkandayaputaranyangterhasil.

More turns. To increase the turning force.

(ii) Bilanganbateriyangdigunakan.Sebab. Number of batteries used. Reason.

Lebihbanyakbateri.Untukmeningkatkanarusdidalamgegelung.

More batteries. To increase the current in the coil.

(iii) Bentukmagnetkekal.Sebab. Shape of permanent magnets. Reason.

Berbentukseparabulatan.Menghasilkanmedanmagnetjejarian.

Semi circular-shaped. Produces radial field.




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(iv) Pilihrekabentukmotorelektrikyangpalingsesuaiyangbolehdigunakanmemutarkankipaspadakelajuanyangtinggi.

Select the most suitable electric motor design that can be used to turn the fan at a high speed.

P

2 Rajah2.1menunjukkansebuahtransformerunggulyangdisambungkepadamotorelektrik12V,40Wa.u.Diagram 2.1 shows an ideal transformer which is connected to a 12 V, 40 W a.c. electric motor.

M


Motor elektrikElectric motor

240 V a.u.240 V a.c. 12 V

GegelungsekunderSecondarycoil

Np=1200lilitan/turns


(a) Nyatakanjenistransformeryangdigunakan. State the type of transformer used.

Transformerinjakturun./Step-down transformer.

(b) (i) Hitungbilanganlilitangegelungsekunderitu./Calculate the number of turns of the secondary coil.

(ii) Motorelektrikituberfungsisecaranormal.Hitungarusyangmengalirdalamgegelungprimeritu. The electric motor functions normally. Calculate the current flow in the primary coil.

(c) Rajah2.2menunjukkantransformeryangsamadisambungkankepadasebuahkomponenelektrikdalamkotakYuntukmenyalakansebuahmentola.t.

Diagram 2.2 shows the same transformer being connected to an electrical component in box Y to light up a d.c. bulb.

M


GegelungsekunderSecondarycoil

Motor elektrikElectric motor

240 a.u.240 a.c. 12 V

Y


NamakankomponenelektrikdalamkotakY./Name the electrical component in box Y.

Diod./Diode.

Kuasaoutput/Output power =40W

\Kuasainput/Input power =40W(Untuktransformerunggul/for idea transformer)

\PP=40W,V

P=240V

PP=V

PIP

\IP=

PP—–

VP

=40W——––240V

=0.1667A =0.17A

NS—–

NP

=V

S—–V

P

NS=

VS—–

VP

×NP

=12V——––240V ×1200turns/lilitan

=60turns/lilitan


MODUL F T 5 Keelektromagnetan 3 Electromagnetism · • Merancang dan menjalankan eksperimen untuk...

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Transcript of MODUL F T 5 Keelektromagnetan 3 Electromagnetism · • Merancang dan menjalankan eksperimen untuk...