Physics for IGCSE & O level - Magnets And Currents (Section 12)

  • 1
    Which device uses an electromagnet to open and close a circuit?
    Sagot
    (B)
    A relay
  • 2
    In a step-down transformer, the number of turns in the primary coil is:
    Sagot
    (B)
    More than the secondary coil.
  • 3
    The equation that relates voltage, current, and power is:
    Sagot
    (A)
    P = VI
  • 4
    How is the strength of an electromagnet increased?
    Sagot
    A
    B
    C
  • 5
    How does a relay work?
    Sagot
    (A)
    By using a small current to control a much larger current.
  • 6
    What is the term for a coil of wire that is free to rotate in a magnetic field in an electric motor?
    Sagot
    (B)
    Armature
  • 7
    Which of the following is a component of a simple electric motor?
    Sagot
    (B)
    An electromagnet