IGCSE Electricity

  1. What name is given to current that only flows in one direction?
    Direct current (dc)
  2. What sort of current is supplied by cells and batteries?
    Direct current (dc)
  3. What do the letters a.c. represent?
    Alternating current
  4. What is the period of an ac wave?
    • The time for a complete cycle
    • Image Upload 1
  5. What is the relationship between the frequency (f) and the time period (T) of an ac wave?
    Image Upload 2

    (T in seconds, f in Hz)
  6. What names are given to the three wires in a UK mains plug?
    • Live
    • Neutral
    • Earth

    Image Upload 3
  7. Some mains cables only have two wires. Which wire is missing?
  8. Which one of the 3 mains wires are circuit breakers and fuses always connected into?
  9. What happens to a fuse if the current exceeds the rating of the fuse?
    Image Upload 4
    It melts, thereby breaking the circuit
  10. Which acts the fastest, a fuse or a circuit breaker?
    circuit breaker
  11. Which appliances are usually earthed?
    • Those with metal cases
    • Image Upload 5
  12. What is the purpose of the earth wire?
    By providing a low-resistance path for the current to flow in the event of a fault, it enables the fuse to blow and break the circuit
  13. What happens when an electrical charge flows through a resistor?
    It gets hot
  14. In a filament lamp, what is most of the electrical energy converted into?
    Heat (wasted)
  15. What is the unit of power?
    Watt (W)
  16. What is the unit of energy?
    Joule (J)
  17. What is the unit of electrical current?
    Amperes (Amps) (A)
  18. What is the unit of electrical charge?
    Coulomb (C)
  19. What is the relationship between energy (E), potential difference (V) , and charge (Q)
    E = V x Q
  20. Are electrons negatively or positively charged?
  21. What causes some insulating materials to become electrically charged when they are rubbed together?
    Electrons are rubbed off one material and onto the other
  22. What happens when two electrically charged objects (that have the same charge) are brought together?
    They repel each other
  23. Give an example of a type of material that electrical charges can move through easily
  24. What is electric current?
    A flow of electric charge
  25. What is the unit of electrical current?
    Ampere (Amp) (A)
  26. How is the size of a current (I) calculated from the total charge (Q) and time (t)?
    I = Q/t
  27. What is the standard unit of electrical charge?
    Coulomb (C)
  28. What is potential difference another name for ?
  29. What component is this graph for?
    Image Upload 6
  30. What is the unit of resistance?
    Ohm  Image Upload 7
  31. If a component has a larger resistance, will the current be larger or smaller?
  32. In a series circuit, what do you know about the current at different points?
    It is always the same
  33. In a series circuit how is the total resistance calculated?
    By adding up the individual resistances
  34. For components connected in parallel what do you know about the potential difference across each component?
    They are all the same
  35. What component is this graph for?
    Image Upload 8
    Filament bulb
  36. Which component only allows current to flow one way?
  37. What component is this graph for?
    Image Upload 9
  38. What happens to the resistance of an LDR as light intensity increases?
    The resistance decreases
  39. What happens to the resistance of a thermistor as temperature increases?
    The resistance decreases
  40. Which component emits light when a current flows through it in a forward direction?
    Light Emitting Diode (LED)
Card Set
IGCSE Electricity
IGCSE Electricity