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NUE 052 - Resistance, Ohms Law and Power Dissipation

  • Resistance is the opposition to current flow in a conductor, measured in Ohms. The symbol is R
  • A good conductor such as copper has a low resistance
  • A good insulator such as mica has a high resistance
  • Ohms law is named after George Simon Ohm who presented his laws back in 1827
  • In his honour the unit of electrical resistance was named the 'ohm'
  • Ohms law relates voltage, current and resistance
  • Power is the rate that energy is used or dissipated, measured in Watts, the symbol is P

    • Use Ohms law to find a value - cover ONE symbol in the triangle to solve the formula

    Volts (V), Amps (I) & Ohms (R)
      
    Watts (P), Volts (V) & Amps (I)
      
     
    Terms used with voltage, current and resistance
    Quantity
    Abbreviation
    Measurement
    Symbol
    EMF
    E
    volt
    V
    Voltage
    V
    volt
    V
    Current
    I
    ampere
    A
    Resistance
    R
    ohm
     Here's a link to an Ohms law calculator for a bit of fun
    Practice Tests are available on the practice test page  
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