Physics P4

    Subdecks (3)

    Cards (57)

    • Magnets have a north and south pole
    • Between two magnets, like poles repel and opposite poles attract
    • Permanent magnets are always magnetic and always have poles
    • Induced magnets can be produced from materials that are magnetic but do not have fixed poles
    • Iron, Nickel, and Cobalt are common induced magnetic materials
    • Magnetic fields are shown using field lines that point from north to south
    • The strength of the magnetic field decreases as distance from the magnet increases
    • Small plotting compasses can be used to plot the shape of a magnetic field around a small magnetised object
    • The Earth's core is magnetic and currents within it create a large magnetic field around the Earth
    • A freely suspended magnetic compass aligns itself with the Earth's field lines and points North
    • Current flowing in a wire produces a magnetic field around the wire
    • The direction of the magnetic field around a wire is dictated by the 'right hand grip rule'
    • Solenoids are formed from a coil of wire with current flowing through
    • Factors affecting the strength of the magnetic field produced by a solenoid include: size of current, length of coil, cross-sectional area, number of turns (coils), and type of core used
    • Two magnets will interact, feeling a magnetic force of attraction or repulsion
    • Fleming's Left-Hand Rule can be used to find the direction of the force between a magnet and a wire
    • An electric motor can be made using permanent magnets and a coil of current-carrying wire that rotates due to induced forces
    • A conductor forms a potential difference as electrons move within it due to a change in the magnetic field
    • Electric generators work by rotating a coil of wire between two permanent magnets to induce a potential difference and produce an alternating current
    • Alternating current constantly changes direction, producing a changing magnetic field
    • Transformers work by inducing a current in a secondary coil through a changing magnetic field created by an alternating current in the primary coil
    • If there are more turns on the secondary coil, a step-up transformer is produced, increasing voltage
    • If there are fewer turns on the secondary coil, a step-down transformer is produced, decreasing voltage
    • Dynamic microphones produce a current proportional to the sound signal by inducing current in a coil of wire that moves within a fixed magnet