Physics - P5

Physics - P5

1. Static Electricty

   • Caused by Friction
     • When INSULATING materials are rubbed electrons are transfered
       • Electrons are negatively charged
       • The particle loosing the electrons gains a positive static charge and negative on the particle gaining
         • Think of it being positive for donating the electrons
         • Which depends on the materials
         • The particles left positively charged are called ions
   • Charges
     • Opposite charges like magnets attract
       • 'Opposites attract'
     • When two charges are the same they repel
     • When the electrons from one object are put on another the object becomes negatively charged
       • They try to repel as they are the same charge
         • As the material is insulating the positions are fixed so the electrons cant move
           • A static charge is the result!

2. Electric Current

   • Current is the flow of charge
     • Electric circuits use conductors (e.g. Metal)
       • In conductors the charges are free to move
       • In a circuit the change flows from the battery and back to it (not used up)
     • Dependent on Voltage and Resistance
       • Current is measured in amps
         • Shown as 'I' in equations
         • Only flows if there is voltage
       • Voltage is measured in volts
         • Voltage is the force pushing the current
       • Resistance is a something that slows a charge
         • Measured in OHMS - Ω
         • Can be components such as a light
     • Amps in easy terms is the number of charged particles flowing past in a second
   • Power - Rate of Energy Transfer
     • Power supply provides energy to change
     • Rate that a supply transfers energy to component
     • Measured in watts
   • • P=Watts V=Volts I=Amps

3. Resistance

   • The voltage in a circuit is relative to the current
     • • Using this graph we find the resistance
         • Steeper the graph the less resistance
         • We use this to find the resistance
         • Resistors get hot when they pass through a purpose resister such as a light as the electrons collide with ions

4. Circuits

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