Physics Y8 P1

• Static electricity


  A build-up of electric charge on an object that does not move in a circuit
• Types of electric charge


  • Positive
  • Negative
• Charges are


  Like charges repel, unlike charges attract
• Subatomic particles


  • Electron
  • Neutron
  • Proton
• Electron


  Negatively charged subatomic particle
• Neutron


  Neutral subatomic particle
• Proton


  Positively charged subatomic particle
• Only electrons are transferred to other objects to create static electricity
• Objects without static electricity have a neutral charge
• Before rubbing, balloon and wool cloth are neutral


  After rubbing, balloon has negative charge and wool cloth has positive charge
• When static electricity produces lightning or a spark, the electrons flow in a current
• Electric field


  A region where there is a force on a charged material or particle
• Current electricity


  The flow of electrons around a circuit
• Current


  The amount of charge flowing in a circuit per second
• Amps


  The unit for measuring current
• Ammeter


  The tool used to measure current
• The electrons in a current come from inside the wire, not the battery
• Incorrect circuits


  Short circuit, incomplete circuit, batteries connected wrong
• Potential difference/Voltage


  The push provided by a cell or battery to make charges move through a circuit
• Volts


  The unit for measuring potential difference
• Voltmeter


  The tool used to measure potential difference
• A voltmeter must be connected to two points in the circuit
• Rating


  The potential difference a component is designed for
• Series circuit


  Components are joined in a single loop
• Parallel circuit


  There are 2 or more paths or branches for the current
• Circuit types


  • Series circuit
  • Parallel circuit
• Lights are usually wired in parallel so if one bulb breaks the others stay on</b>
• In a series circuit, the current is the same everywhere
• In a series circuit, the potential difference is shared and the voltages across components add up to the battery/cell voltage
• In a series circuit, adding another light bulb


  Makes the current decrease
• In a parallel circuit, current is shared and the currents in the branches add up to the total
• In a parallel circuit, the potential difference is the same everywhere
• In a parallel circuit, adding another branch


  Makes the current increase
• Resistance


  How easy or difficult it is for charges to flow through a component
• Ohms


  The unit for measuring resistance
• Ω


  The symbol for ohms
• Equations for voltage, current, resistance


  • Voltage = Current x Resistance
  • Current = Voltage / Resistance
  • Resistance = Voltage / Current
• Conductors


  Have low resistance and conduct electricity well
• Insulators


  Have high resistance and conduct electricity poorly
• Magnet


  A piece of metal with a strong attraction to another metal object