P2a

• What does a break in a circuit do?

  Stops the current
• What does completing a circuit do?

  Allows current to flow
• What is the function of a diode in a circuit?

  Only allows current to flow one way

  
• How does fixed resistance affect current?

  Reduces current
• What is the effect of changeable resistance on current?

  Reduces current
• What does an LED do?

  Emits light
• What happens when current is too high in a circuit?

  Breaks circuit
• What does a voltmeter measure?

  Potential difference
• What does an ammeter measure?

  Current
• How does temperature affect resistance in a thermistor?

  Resistance decreases as temperature increases
• What are the key definitions in electrical circuits?

  • Charge: Number of electrons, measured in coulombs (C)
  • Current: Flow of charge, measured in amps (A)
  • Potential difference: Energy per electron, measured in volts (V)
  • Resistance: Amount an object reduces current, measured in ohms (Ω)
• What is a series circuit?

  A single closed loop for electrons
• What is a parallel circuit?

  Two or more closed loops
• How does a thermistor work?

  Resistance decreases as temperature increases
• How does a light-dependent resistor work?

  Resistance decreases as light intensity increases
• What are the rules for series circuits?

  • Same current through each component
  • Potential difference is of the power supply shared by all components
  • Total resistance is the sum of individual resistances
• What are the rules for parallel circuits?

  • Total current is the sum of currents in each loop
  • Potential difference along each loop is equal to the battery's p.d.
  • Adding loops reduces overall resistance
• What is the formula for charge flow?

  Q = I t
• What is the formula for potential difference?

  V = I R
• What is the I-V graph behavior of a fixed resistor?

  • Ohmic behavior: resistance does not change
  • Current is directly proportional to potential difference
• What is the I-V graph behavior of a filament lamp?

  • Resistance increases as temperature increases
  • Current increases as potential difference increases but lessens over time
• What is the I-V graph behavior of a diode?

  • Current increases in one direction with potential difference
  • Current remains zero when potential difference is reversed

  
• What is static charge?

  • Charge can build up on insulated objects
  • Electrons move when insulators are rubbed together
• What happens when two insulators are rubbed together?

  Electrons move from one object to another
• What occurs when an object loses electrons?

  It becomes positively charged
• What occurs when an object gains electrons?

  It becomes negatively charged
• How do charged spheres behave in an electric field?

  • Positively charged: arrows point away
  • Negatively charged: arrows point towards

  
• How does the density of field lines relate to charge strength?

  More lines indicate a stronger charge
• How does distance affect the force between charged particles?

  Force is stronger when closer
• What is the relationship between potential difference and current?

  • Potential difference causes current to flow
  • Current flows from high p.d. to low p.d.
• What happens during an electric shock?

  Current passes through you into the ground
• What are the types of charge interactions?

  • Same charge: repel
  • Opposite charge: attract
• What is charge measured in?

  Coulombs
• What is current measured in?

  Amps
• What is p.d. measured in?

  Volts
• What is resistance measured in?

  Ohms
• What happens when you get an electric shock ?

  When you touch something with a high p.d current will pass through you into the ground.