7.1 analysing electric fields and charge flow
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Chapter 7: Electric
7.1 Analysing electric fields and charge flow
What are atoms?
Matter is made up of tiny particles called atoms
An atom consists of..
• Center of atom– Nucleus• Protons : Positive charged• Neutrons : Neutral / uncharged• Electrons surround : negative
++
+ ++
+
--
--
--
Nucleus
Neutrons
Protons
Electrons
Neutral charged
Positive charged
Negative charged
+
-
Electric charge:
Symbol: QUnit: Coulomb
C
One ProtonElectron
1.6 x 10-19 C-1.6 x 10-19 C
Charge
A body is:
- +NNegatively Charged Neutral Positively Charged
+++-
-
--
-- ++
+ ++
+
--
--
-- ++
+ ++
+
-
-
-
More negative charge than positive
Equal negative and positive charge
More positive charge than
negative
Forces acting on two bodies:
Same Net Charges
Different Net Charges
The force causes movement of electrons or flow of charges
- - + +Repel
- -++Attract
Electric Current
Current
I =Q
t
Charge
Time
SI Unit: Ampere
A
Electric FieldAn electric field is a region in which an electric charge experiences an electric force (attraction or repulsion)
Created from a positively charged sphere in the spaces surrounding it
Electric Field
+A negative charged body when placed at any point in this region is pulled towards the charged sphere
-AttractiveForce
Represented by series of arrowed linesElectric Field
+ -Electric field lines
Electric Field Linesindicate both:
Magnitude
Direction of the field
Direction of the force acting on a charged body placed at that point
+
-
Never cross each otherElectric Field Lines
+WRONG
+CORRECT
Electric field lines are most dense around objects with greatest amount of charge
Electric Field Lines
+Less DenseLess Charge
More DenseMore Charge
+
Photo credits
• Flickr/magnifier test coil/tesla1000• Flickr/phenomena/amsterdam today• Flickr/I hope mom doesn’t see
this/tayyywilson• Flickr/rural electricity/kevin dooley• Flickr/green wheat/bernat casero
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