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Physic chapter 18 (electric quantities), Resistance, the work done (J) per…

- - - - rate of + electric charge + pass a point in a circuit
    - - Ammeter (2types)
        
        analogue meter : -needle + move across scale -> position on scale
        
        Digital meter : -direct read-out figure + no judgement on reading
        
        !theory : 0 resistance -> connected in series. ATP : wrong result <- not 0, is small number cause wrong
        
        !connect wrong -> negative reading
      - galvanometer
        
        measure tiny currents
    - - -Increase p.d push it (~e.m.f) + easier resistance
  - - - 2 or more electrical cells + connected in series (end-to-end)
    - - -like a switch + allow current go one direction
      - acts as insulator until enough voltage -> conductor
  - - - Electric current + flow in same direction + all the time (dòng điện 1 chiều)
    - - electric current + periodically + changes direction
  - - - components connected in a line between other components
  - - - !conventional current : opposite direction vs flow of electrons
  - - - energy transfered/work done per unit of charge thru components/as push of current
    - - Voltmeter (2 types)
        
        Analogue display (with needle)
        
        digital display
        
        always connect in parallel (~~components connected in branches across circuit)
    - - e.m.f (electro motive force) # not a force
        
        the electrical work done (joule) per unit of charge pushed by a source ;
- - - - def
        
        -has constant resistance -> I-V characteristic : a straight line (~I proportional to V)
      - if voltage double -> current double
- - - - use 1kWh -> 1000 W x 1 hours => 3.6 x 10^6 J (a big number) (convenient) (~ a unit of energy)
        
        measured |
        
        electrical meter
      - Define kWh