Electromagnet 8.1 Student Copy
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Transcript of Electromagnet 8.1 Student Copy
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8/18/2019 Electromagnet 8.1 Student Copy
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FORM 5© COPYRIGHT BY SUPER EDUCATION GROUP (J
CHAPTER 8: Electr !"#$et8%& r'# t "$ #r'* r+le
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N S
Direction of magnetic elds
CHAPTER 8: Electr !"#$et
Newton Memory
1. Electromagnet is a temporary magnet consist of a long coil of insulated copper wire carrying electric current wound on a soft ironcore./temporary magnet produces by the flow of current.
2. The magnetic effect of current is called electromagnetism whichmeans that electricity produces magnetism.
3.
PREPARED BY JJ MR,EON P"#e &© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
Permanent Magnet Temporary Magnet"% it is made of steel-% the strength of the
magnetic field isnormally constant and isnot adjustable
"% it is made of iron cobalt andnic!el
-% The strength of the magneticfield is adjustable or random.
c% both ha"e similar magnetic effect.% both magnet ha"e two pole #North Pole and $outh Pole%
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CHAPTER 8: Electr !"#$et
&.1' Magnetic Effect of a current(carrying conductor
Electromagnets
1. Conductor is a material that can flow ……………………..
2. Electromagnetism is the study of the relationship between ……………….and ………………..
3. ………………………. are produced by electrically charged objects.
4. A bar magnet produces the ………………………around it. raw the pattern of the magnetic fields produced around a bar magnet below
PREPARED BY JJ MR,EON P"#e .© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
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N S
S /t 'r $ c re
I$0+l"te 1're
*'$0
DC 0+**l2
'tc
S /t 'r $ c re
I$0+l"te 1're
*'$0
DC 0+**l2
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CHAPTER 8: Electr !"#$et
!. "how the deflection of the pointer of the compasses.
#. $agnetic fields also can be produce by an electric current in a wire.
%. Electromagnet is a ………………… magnet. &t is made by winding a coil of insulated wire round a softiron core.
'. (sing the diagram) complete the steps to switch on the magnetism effect.
PREPARED BY JJ MR,EON P"#e 3© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
Electromagneticfled
So t ironcore is
magnetis
Currentows
S1'tc '0cl 0e
Attracts pins
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Direction of magnetic elds
CHAPTER 8: Electr !"#$et
). Magnetic *ield due to a +urrent in $traight ,ire
Method ' using +ompass and -ron filling used to map out the pattern of the magnetic field
1. (sing ight(hand /rip ule ) draw the direction of current flows and pattern of magnetic fields formed
2. ight(hand /rip ule states that the thumb of the right hand points to the direction of current flowand the other four curled fingers points to direction of its ………………….
3. raw the same patterns from the top *iews as follows together with the direction shown by thecompasses.
$eans that a wire carrying current ………….. the plane of paper
$eans that a wire carrying current …………... of the plane of paper
PREPARED BY JJ MR,EON P"#e 4© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
magnetic
into
out
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CHAPTER 8: Electr !"#$et
E0ercise &.1
1. +wo small plotting compasses , and - are placed near a long straight wire carrying a current as shown.
"how the directions shown by the pointers of the compasses
4. &n the diagram below) the compasses are put under the conductor. Can you draw the direction shown by
compasses and what happen if the compasses are put on the conductor
. Magnetic *ield due to a +urrent in a +ircular +oil
!. raw the direction of current flows and pattern of magnetic fields formed.
PREPARED BY JJ MR,EON P"#e 5© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
P
T e c !*"00 '0*+t UNDER t e
T e c !*"00 '0*+t UNDER t e
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CHAPTER 8: Electr !"#$et
#. +he direction of magnetic field also can be determined using the ight and /rip ule .
/ 0otes The field strength is the strongest at the center area because combination from two sources
+he magnetic field strength can be increased by increasing the current flow in the wire.i adding more battery or cell in the series ciruitii reducing the resistance by busing the rheostatiii using a shorter wirei* using a thic er wire
+he strength of magnetic field of the coil wire increase wheni when the current in the coil increasedii the number of turn of coil increase
iii a coil with smaller radius is used
+. Magnetic *ield due to a +urrent in a $olenoid
1. $olenoid is combination of coils of wire wounded around on some surface or wounded around an iron
core.
PREPARED BY JJ MR,EON P"#e 6© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
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CHAPTER 8: Electr !"#$et
2. +o chec the poles formed) see from beside of the
solenoid. &f the current flow is cloc!wise ) the polarity on
that side is …………………… but) if the current flow is
anti(cloc!wise ) the polarity on that side is
……………………
the strength of magnetic field of solenoid increase when
#i% the magnitude of current increase
#ii% the number of turns is increased
#iii% a soft iron core is placed in the solenoid
PREPARED BY JJ MR,EON P"#e 7© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
North
South
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CHAPTER 8: Electr !"#$et
#i"%the turns of the wire are pushed closer together so that the solenoid become shorter
produce higher field strength.
4.*actors that affects the strength of an electromagnet
15.
+he
higher the number of paper clips attracted to the solenoid shows the …………..….the strength of that
electromagnet.
As a conclusion) fill the table below
Factors Conditions Number of paper clips
attracted
Affects on the strength of
electromagnetic fields 0umber of turnsElectric current(se of normal iron6core
-nil-(se of soft6iron core
PREPARED BY JJ MR,EON P"#e 8© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
Manipulated Responding Fixed 0umber of turns Number of paper clips attracted Current) types of coreCurrent 0umber of paper clips attracted 0umber of turns) types of core+ypes of core 0umber of paper clips attracted Number of turns, Current
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CHAPTER 8: Electr !"#$et
)pplications of Electromagnet1. +here are many applications of electromagnets. 7abel and describe the figure of each apparatus stated in
the
table
below with its simple wor 6frame.
PREPARED BY JJ MR,EON P"#e © COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
1) Electric bells 01'tc &%When the switch is closed, the
current fow will magnetized the so t-
iron core
.% The so t iron armature is pulled
toward electromagnet and hit the
gong
3% At the same time, the contact will
open and stop the current fows. No
electromagnet.
4%The spring mechanism brings the
armature back to its original position
5%The contacts close again and similar
process is repeated.
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c $t"ct
0*r'$#0
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# $#
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CHAPTER 8: Electr !"#$et
2) Electromagnetic elays
!) Telephone earpieces//spea"ers
PREPARED BY JJ MR,EON P"#e &© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
&%When the switch A is closed, a small
current fows in input circuit will
magnetized the so t-iron core
.% The so t iron armature is attracted
toward electromagnet
3% At the same time, the spring contactclosed
4% A large current fows to high voltage
circuit to operate the electrical
apparatus.
0 /t9'r $c re t '#
; lt"#e c'rc+'t
&% A var ing current received rom the
caller in telephone line
.% The var ing current passes through
solenoid and magnetized the so t-
iron core
3%The electromagnet varies in
magnetic strength according to the
veri ing current
4%The allo diaphragm will attract toelectromagnet b var ing orce
5%!ound produced as compression and
rare action o air particles
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CHAPTER 8: Electr !"#$et
5% +ircuit brea!ers
6% 7ifting Magnet
PREPARED BY JJ MR,EON P"#e &&© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
S /t9'r $c re
All 2'"* r"#!
Per!"$e$t!"#$et
0 le$ '
automatic switch to
breaks circuit to open when
current becomes too large
It0 *er"te "0
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CHAPTER 8: Electr !"#$et
E0ercise &.1.2
1. A magnetic field is produced by the current in a long straight wire. +he strength of the magnetic field
increases if.
A +he magnitude of the current increases
8 +he distance from the wire increases
C +he length of the wire increases
2. 9hich of the following is true about the magnetic field produced by a current in a flat circular coil .
A &t is uniform inside the coil
8 &t is the wea est at the centre
C &t is the strongest at the centre+here is no magnetic field outside the coil
3. 9hat is the effect of placing a piece of soft iron core inside a solenoid carrying current
A +he resistance of the solenoid decreases
8 +he current in the solenoid increases
C +he magnetic field becomes stronger
4. An electromagnet is used in these apparatus e0cept
PREPARED BY JJ MR,EON P"#e &.© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
N rt P le
S +t P le
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CHAPTER 8: Electr !"#$et
A a compass
8 an a.c dynamo
C a mo*ing coil ammeter
a telephone earpiece
!. 9hich electromagnet is the strongest
A 8 C
PREPARED BY JJ MR,EON P"#e &3© COPYRIGHT BY SUPER EDUCATION GROUP (JOHOR JAYA)
=4>9=.>9