7.1 electrostatics
TRANSCRIPT
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Chapter 7 Electricity
Electrostatics
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Learning Outcomes:
• describe what electrostatics is,
• state the types of static electrical charges,
• state the properties of static electrical charges,
• describe how static electrical charges can beproduced in some materials,
• describe ways to detect static electrical charges,
• explain everyday phenomena caused by static
electrical charges,
• state the safety measures to be taen when
dealing with static electricity!
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Electrostatics
• Electrical charge that is caused by friction
• "tatic electricity
• Electricity that does not move but stays
still on ob#ect
• $roduced in materials through friction
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%ypes of static
electrical
charges
$ositive charge &'( )egative charge &*(
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Characteristics of static electric
charges
• Lie charges repel
• +epulsive force attractive force called
electrostatic force
' ' ' ' ' '' '
' ' '
'
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Characteristics of static electric
charges
• Lie charges repel
• +epulsive force attractive force called
electrostatic force
* * * * * ** * * * *
*
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Characteristics of static electric
charges
• -nlie charges attract
• +epulsive force attractive force called
electrostatic force
' ' ' * * * ' ' ' *
* *
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%ype of charge produced
' *
.lass "il cloth
Cellulose acetate "il cloth, woollen cloth
"il cloth /ard rubber
+ubber &balloon( )ylon
0oollen cloth +ubber &balloon(,polythene
1ur 2alloon, ebonite,polythene
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Observation
3aterial Observation
2its of paper 444444444444 the plastic ruler
0ater stream 444444444444 the plastic ruler
Electroscope %he gold leaf 444444444
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Electroscope
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Observation
3aterial Observation
2its of paper 5ttracted towards the plastic ruler
0ater stream 5ttracted towards the plastic ruler
Electroscope %he gold leaf diverged
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5nalysis
6! stationarydo not move
8! %ransfer of electrons
9! Electrostatic charges
! Charged, not charged
;! $ositive, negative
<! electrical charges
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Conclusion
6! Electrostatic charges
8! electroscope
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"tatic electrical charges
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Observation
• $olythene*polythene
• "trips 44444 each other
• 444444444 force
• $olythene*cellulose acetate
• "trips 444444 each other
• 444444444 force
repel
attract
+epulsive
5ttractive
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5nalysis
6! a( %hey repel
b( %hey attract
8! Electrostatic force
9!
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Electrostatic $henomena
• Occurrence of lightning
• "par plug
• )ylon clothes
• Combing hair
• Electronic lighter ++
+
+
+
+
= = = = = = = = = =
= = = = = = = = = =
= = = = = = = = = =
= = = = = = =
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Electrostatic $henomena
• /igh building = lightning conductor
• Oil taner = metal chain
• 5eroplane = special tyres
++ ++++
+++
- -
- - - - - --
++
+ ++
++ + +
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Electrostatic phenomena
• moves
• rubs
• prevent
• Earth
• metal
• touches
• spars
• fire