Electric Current

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Electric Current

• Mr. Kidwell

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Flow of Charge

• A charge flows when there is a potential
  difference
• When the ends of an electric conductor are at
  different electric potentials, charge flows from
  one end to the other
• The flow of charge will continue until both ends
  reach a common potential
• Ex Difference in water level

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Electric Current

• Electric Current the flow of electric charge
• Solid conductors the electrons can move around
  freely carrying the charge
• Electric Current is measured in amperes (A)
• amp 1 coulomb of charge per second
• 1 coulomb 6.24 billion electrons

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Electric Current Cont

• A current carrying wire does not have a net
  electric charge
• While the current is flowing, negative electrons
  swarm through the atomic network
• The number of electrons in the wire is equal to
  the number of protons
• The number entering is the same as the number
  leaving
• The net charge is zero

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Voltage Sources

• Voltage Source something that provides a
  potential difference
• Dry Cells, Wet Cells and Generators supply energy
  that allows charges to move
• Dry/Wet Cells chemical energy converted to
  electrical energy
• Generators mechanical energy to electrical energy

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Electric Resistance

• The amount of charge that flows depends on the
  voltage provided by the voltage source
• Electric Resistance The resistance of a material
  to the flow of electric current through it
  measured in ohms
• Depends on the resistance the conductor provides

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Electric Resistance

• Thick wires have less resistance than thin wires
• Electric resistance also depends on temperature
• The greater the jostling about of atoms within
  the conductor, the greater resistance the
  conductor offers to the flow of charge

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Ohms Law

• Electric Resistance is measured in units called
  ohms
• Resistance voltage
• current
• Current voltage
• resistance

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• What is the resistance of an electric frying pan
  that draws 10 amperes of current when connected
  to a 120-volt circuit?
• Resistance voltage
• current
• Measured in ohms

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• How much current is drawn by a lamp that has a
  resistance of 110 ohms when a voltage of 60 volts
  is pressed across it?
• Current voltage
• resistance
• measured in amperes.

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