Magnetism & electromagnetism

    Cards (46)

    • Magnetic metals
      • Iron
      • Steel
      • Cobalt
      • Nickel
    • Steel
      An alloy of iron containing the element carbon
    • Two North Poles
      Repel
    • Two South Poles
      Repel
    • North Pole

      Attract South Pole
    • Soft magnetic material
      Loses magnetism easily
    • Hard magnetic material

      Maintains its magnetism
    • Hard magnetic material
      • Steel
    • Soft magnetic material
      • Iron
    • Magnetic field line
      The space around a magnet whereby magnetism can be detected
    • Determining magnetic field line shape
      1. Using iron filings
      2. Using plotting compasses
    • Solenoid
      A cylindrical coil of wire
    • Right-hand grip rule
      A way of showing the direction of magnetic field lines
    • Uniform magnetic field
      • Magnetic field lines are evenly spaced and parallel
    • Inducing magnetism in an object
      Place magnetic metal object in magnetic field of permanent magnet
    • Electromagnet
      Constructed by connecting a wire to a circuit and running a current through it
    • Increasing strength of magnetic field of wire carrying current
      1. Increase current
      2. Wrap wire into a solenoid
    • Increasing magnetic field of a solenoid
      1. Add more turns of coil
      2. Add an iron core
    • Increasing current
      Increases magnetic field strength
    • Motor effect
      A wire carrying a current in a magnetic field experiences a force causing it to spin
    • Fleming's left-hand rule
      A way of determining the direction of the force on a wire carrying a current in a magnetic field The thumb represents the force, the first finger the magnetic field, and the second finger the current
    • ( left hand rule )The thumb represents the force, the first finger the magnetic field, and the second finger the current
    • The motor effect is used in electric motors and speakers
    • When the switch is closed, current flows around the circuit creating a temporary magnetic field that interacts with the permanent magnetic field to create a force that turns the coil
    • To make the coil spin in the opposite direction

      1. Switch the direction of the current
      2. Swap the magnets over
    • To make the coil spin more slowly
      1. Reduce the current
      2. Reduce the voltage
      3. Use a weaker magnetic field
    • Magnetic field line
      Line that shows the direction of the magnetic field
    • The magnetic field lines are not uniform, they are parallel but unevenly spaced
    • Electromagnetic induction
      How voltage or current may be induced
    • If you have a magnetic field and current, you get force. If you have force and magnetic field, you can get current - this is the basis of electromagnetic induction
    • The magnetic field in the region shown inside the dotted square is not uniform because the lines are different spaces apart and they are flowing in the same direction, so they are parallel to each other
    • If you put in a magnetic field and you put in current
      You get force
    • If you put in the force and you put in the magnetic field
      You should be able to make current
    • Electromagnetic induction
      1. If a wire is moved into a magnetic field at right angles
      2. A voltage will be induced
      3. If it's connected up to a complete circuit, that's where your current comes from
    • Fleming's right-hand rule
      Used to determine the direction of the force, magnetic field, and current
    • A generator is a machine which creates electricity
    • Ways to increase the size of the induced current
      • Use stronger magnets to have a stronger magnetic field
      • Move the wire more quickly
    • Use of generators in everyday life

      • Bicycle dynamo
    • How a bicycle dynamo works
      1. The bicycle wheel turns a magnet located within a coil
      2. The magnetic field of the magnet cuts the surrounding coil which induces a current
    • Relay switch
      • Used to turn on very large currents
      • A safety device to prevent people from touching high voltage supplies
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