Topic 10: Electricity and circuits

    Cards (34)

    • What is the structure of the atom?
      Positively charged nucleus with negatively charged electrons
    • What are the subatomic particles and their charges?
      • Proton: +1 charge, mass 1
      • Neutron: 0 charge, mass 1
      • Electron: -1 charge, mass 0.0005
    • What is a series circuit?
      A closed circuit where current is the same everywhere
    • What is a parallel circuit?
      A branched circuit where current splits into multiple paths
    • What does potential difference represent?
      Energy transferred per unit charge
    • How is potential difference measured?
      With a voltmeter placed in parallel across a component
    • What happens when there is a potential difference in a closed circuit?
      Current will always flow
    • What is the formula for energy transferred?
      E = QV
    • What is the unit of current?
      Amps
    • How is current defined?
      Rate of flow of charge (electrons)
    • How is current measured?
      With an ammeter placed in series
    • What happens to current with greater resistance?
      Current decreases as resistance increases
    • What is a variable resistor used for?
      To change the amount of resistance in a circuit
    • What are the characteristics of series circuits?
      • Components connected end to end
      • Current flows through all components
      • Potential difference is shared across the circuit
      • Total resistance is the sum of individual resistances
    • What are the characteristics of parallel circuits?
      • Components connected separately to the power supply
      • Current flows through each component separately
      • Potential difference is the same across all branches
      • Total resistance is less than the smallest branch resistance
    • What is the formula for total resistance in series?
      R<sub>T</sub> = R<sub>1</sub> + R<sub>2</sub>
    • Why does resistance increase with length?
      Longer length means more atoms for electrons to pass
    • How does cross-sectional area affect resistance?
      Thinner wires give greater resistance
    • What happens to resistance in an LDR with increased light intensity?
      Resistance decreases with greater light intensity
    • What is the function of a diode?
      Allows current to flow in one direction only
    • What is the relationship between power, current, and voltage?
      Power is directly proportional to current and voltage
    • What is the formula for electrical power?
      P = IV
    • What is the difference between AC and DC?
      AC varies continuously, DC flows in one direction
    • What is the mains supply voltage in the UK?
      230V
    • What color is the live wire in a plug?
      Brown
    • What is the purpose of the earth wire?
      To prevent appliances from becoming live
    • What happens if the live wire touches the metal casing?
      The appliance becomes live, risking electric shock
    • What does a fuse do?
      Melts to break the circuit if current is too high
    • What is power rating?
      Power of the appliance when in use
    • What are the testing relationships for varied wire resistance?
      • Use wires with resistance from 10 to 300 ohms
      • Connect to DC voltage sources (2V to 30V)
      • Measure current for each voltage
      • Plot graph of potential difference against current
    • What are the testing relationships for filament lamps?
      • Connect to DC voltage sources (2V to 12V)
      • Measure current for each voltage
      • Plot graph of potential difference against current
    • What are the testing relationships for diodes?
      • Connect to DC voltage sources (1V to 12V)
      • Measure current for each voltage
      • Reverse connection to measure negative potential differences
      • Plot graph for positive and negative potential differences
    • What are the testing relationships for LDRs?
      • Use constant voltage of 12V
      • Measure current at varying light intensities
      • Plot graph of resistance against light intensity
    • What are the testing relationships for thermistors?
      • Use constant voltage of 12V
      • Measure current at varying temperatures
      • Plot graph of resistance against temperature