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P2- Electricity - Coggle Diagram

- - - - current has to flow through all of them (only one path)
  - - - current has more than one path to take
    - - at a junction current splits depending on the amount of resistance
  - - - Friction causes electrons in the outer shell of the atom to be rubbed off, depending on how strongly the electrons are bound to the nucleus
      - These charges only build up in insulators
      - Polythene rod(-) & dry cloth(+)
      - Perspex rod(+) & dry cloth(-)
      - Earthing- when an object with a large static charge loses it's electrons to the Earth (a reservoir of electrons)
    - - Positive away; negative towards
      - (drawing of electrical fields)
      - Like charges repel; opposites attract
      - non-contact force
  - - - Charge flows from + to - via electrons
    - - Thermistor
        
        used to control heating circuits
        
        as temp. increases, resistance decreases
        
        negative temp. coefficient
      - LDR
        
        dependent on light intensity
        
        the brighter, the less resistant
        
        (control circuit)
        
        Too little light detected= current can't flow through that part of the circuit (too much resistance
        
        Goes a different pathway so current can reach the bulb (and opens up other pathways)
      - Ohm's law- current through a resistor at a constant temp. is directly proportional to pd across the resistor
      - due to collisions between moving electrons and the ion lattices within the objects
      - larger current= more collisions= increased resistance (lattice vibrates more)
      - Resistor- directly proportional (constant resistance)
      - Diode- semi-conductor (allows current to flow one way and not the other)
      - Lamp- gets hotter, more resistance (more collisions as more vibrations)