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== Voltage sources – batteries and generators ==
== Voltage sources – batteries and generators ==
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[[File:Electromagnetism_%20Resource_Material_Subject_Teacher_Forum_September_2011_html_bb112d6.png]]A
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[[File:CurrentElecticity1.png|left]]
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battery or a generator does work to pull electrons from positive
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A battery or a generator does work to pull electrons from positive
charges. In a battery, this is done using chemical reactions; where
charges. In a battery, this is done using chemical reactions; where
the energy of the chemical bonds is converted into electrical energy.
the energy of the chemical bonds is converted into electrical energy.
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induction.
induction.
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[[File:Electromagnetism_%20Resource_Material_Subject_Teacher_Forum_September_2011_html_70ab754b.jpg]]
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[[File:CurrentElecticity2.jpg]]
The cell shown here uses dilute sulphuric acid as
The cell shown here uses dilute sulphuric acid as
the electrolyte. One of the electrodes is carbon ; the other is
the electrolyte. One of the electrodes is carbon ; the other is
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after a while, all the zinc will dissolve and the cell will be dead.
after a while, all the zinc will dissolve and the cell will be dead.
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== Electrical resistance ==
== Electrical resistance ==