Electricity

• What are the two types of circuits?

  Series and parallel
• What happens to the current in a series circuit?

  The current is the same throughout the circuit
• What occurs when the switch in a circuit is closed?

  Delocalised electrons move at the same time
• How do electrons behave in a circuit?

  They move slowly and carry energy
• How is current measured?

  In Amps using an ammeter
• What is the formula for charge?

  Charge (C) = Current (A) x Time (s)
• If the current is 4A for 3 seconds, what is the charge?

  $12C$
• How is potential difference measured?

  In volts using a voltmeter
• What is the voltage in parallel circuits?

  Voltage is the same on each branch
• How is voltage distributed in series circuits?

  Voltage is split among components
• Why is the voltage the same across both bulbs in a parallel circuit?

  Because voltage is the same on each branch
• What are the component symbols in electricity?

  • Qo: Switch (open)
  • oo: Switch (closed)
  • Cell: Battery
  • Diode
  • Resistor
  • Variable resistor
  • LED: Light Emitting Diode
  • Bulb
  • Fuse
  • Voltmeter
  • Ammeter
  • Thermistor
  • LDR: Light Dependant Resistor
• What are the characteristics of current in series and parallel circuits?

  • Series:
  • Current is the same throughout
  • Parallel:
  • Current is split among branches
• What is the relationship between voltage and components in series and parallel circuits?

  • Series:
  • Voltage is split among components
  • Parallel:
  • Voltage is the same on each branch
• What does Ohm's Law state about potential difference?

  Potential Difference = Current x Resistance
• How does increasing the length of a wire affect resistance?

  It increases resistance
• What happens to resistance when the thickness of a wire is increased?

  Resistance decreases
• What role do metal ions play in a wire's resistance?

  They attract or repel electrons
• How does higher resistance affect current flow in a wire?

  It makes it harder for current to flow
• What effect does adding components in a circuit have on resistance?

  It increases the resistance
• What is the formula for total resistance in parallel circuits?

  $\frac{1}{R_T} =$$\frac{1}{R_1} +$$\frac{1}{R_2}$
• How does a thermistor's resistance change with temperature?

  • Temperature increases: resistance decreases
  • Temperature decreases: resistance increases
• How does a Light Dependent Resistor (LDR) respond to light intensity?

  • Light intensity increases: resistance decreases
  • Light intensity decreases: resistance increases
• What is the characteristic of a fixed resistor?

  Resistance is constant
• How does a filament lamp behave in terms of resistance?

  It has high resistance when hot
• What is the behavior of a diode in terms of resistance?

  It has very high resistance until conducting
• How does temperature affect resistance in materials?

  Higher temperature generally increases resistance
• What is the relationship between resistivity and resistance?

  Resistance is linked to resistivity and length
• What happens to current in a circuit with high resistance?

  Current flow is reduced
• What is the effect of adding more resistors in series on total resistance?

  Total resistance increases
• How does the resistance of a wire change with its length?

  Longer wires have higher resistance
• What is the relationship between voltage, current, and resistance in a circuit?

  Voltage equals current times resistance
• What does a high resistance in a diode indicate?

  Zero current until conducting
• How does a lamp's resistance change with temperature?

  Resistance increases as temperature rises