Physics for You

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Learning Objectives
P1a 9b
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Chapter 31 Edexcel topic P1a 9b Current and
Resistance
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Current and ResistanceYou should learn
Chapter 31

• A complete circuit is needed for a current to
  flow
• All metals are good conductors
• Electricity tends to travel by the easiest path
• Current is measured by an ammeter, placed in
  series in a circuit
• Potential difference is measured by a voltmeter,
  placed in parallel.

P1a 9b
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Current and ResistanceYou should learn
Chapter 31

• The resistance of a wire depends on
• - its length,
• - its cross-sectional area,
• - the substance it is made of,
• - its temperature.

P1a 9b
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Current and ResistanceYou should learn
Chapter 31

• On a current voltage graph, the steeper the
  graph, the lower the resistance
• A light-dependent resistor (LDR) changes its
  resistance when light shines on it. In bright
  light it has a low resistance
• A thermistor changes its resistance when its
  temperature changes.When it is hot it has a low
  resistance.

P1a 9b
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