P2: Series & Parallel Circuits Physics GCSE

• What are the two ways of joining electrical components?

  In series and in parallel
• What is a series circuit?

  A circuit with components connected end to end
• What is a parallel circuit?

  A circuit with components on separate branches
• What are the characteristics of series circuits?

  • Current is the same at all points
  • Total potential difference is shared
  • Total resistance is the sum of individual resistances
• How is the current in a series circuit described?

  The current is the same at all points
• How is the total potential difference in a series circuit calculated?

  It is shared between the components
• If a battery is marked 12 V in a series circuit with two lamps, what is the potential difference across each lamp?


  6 V across each lamp
• How is total resistance calculated in a series circuit?

  It is the sum of each component's resistance
• If each lamp in a series circuit has a resistance of R, what is the total resistance?

  2R for two lamps
• What are the characteristics of parallel circuits?

  • Total current is the sum through components
  • Potential difference across each component is the same
  • Total resistance is less than the smallest resistor
• How is the total current in a parallel circuit described?

  It is the sum of currents through components
• What is the potential difference across each component in a parallel circuit?

  It is the same across each component
• If a battery is marked 12 V in a parallel circuit, what is the potential difference across each lamp?

  12 V across each lamp
• How does the total resistance of two resistors in parallel compare to the smallest individual resistor?

  It is less than the smallest individual resistor
• Why does the total resistance decrease in a parallel circuit?

  Because each resistor creates an extra path
• What are the advantages of parallel circuits?

  • Components can be individually controlled
  • If one component fails, others continue to work
• What happens to the overall resistance when more resistors are added in series?

  Overall resistance increases
• How is total resistance calculated for resistors in series?

  It is the sum of their individual resistances
• If the combined resistance of two resistors in series is 60 Ω, what is the resistance of R if one resistor is 30 Ω and the other is 10 Ω?

  20 Ω
• What happens to the total resistance when resistors are connected in parallel?

  Total resistance decreases
• Why does adding a resistor in parallel decrease total resistance?

  It creates an extra path for charge flow
• What is a fundamental concept about circuits?

  • Changing one parameter (current, p.d., resistance) affects all others
• How does current behave in a series circuit?

  It is the same at all points
• How does current behave in a parallel circuit?

  It splits at junctions
• How is voltage shared in a series circuit?

  It is shared between the components
• How is voltage across components in a parallel circuit described?

  It is the same across each component
• What is the difference in total resistance between series and parallel circuits?

  • Series: Total resistance is the sum of resistances
  • Parallel: Total resistance is less than the smallest resistor
• What is the definition of direct current (d.c.)?

  A current flowing in one direction
• What is a disadvantage of series circuits?

  If one component fails, all stop working
• What is the potential difference across a cell in a d.c. circuit?

  It is in one direction only
• What produces direct current?

  Electric cells or batteries
• What is a characteristic of alternating current (a.c.)?

  It continuously changes direction
• What is the behavior of current at junctions in a parallel circuit?

  It splits into individual branches
• How does the number of components affect resistance in a series circuit?

  More components increase overall resistance
• Why does the charge experience more collisions in a series circuit?

  Because it has to pass through multiple components
• What happens to the charge in a parallel circuit?

  It has more than one pathway to take
• What is the effect of adding a resistor in series?

  It increases the total resistance
• How does the current behave when resistors are added in parallel?

  More charge can flow overall
• What is the relationship between current and resistance in a circuit?

  Changing one affects the others
• What is the summary of series and parallel circuits?

  • Series: Current same, voltage shared, resistance adds
  • Parallel: Current splits, voltage same, resistance decreases