Magnetism and Electromagnetism

• What is a permanent magnet?

  A magnet that can produce its own magnetic field and will repel and attract other magnets, made from a magnet material and cannot be demagnetised.
• What is a hard magnetic material?

  Magnetised when an external field is applied and stay magnetised permanently when the external field is removed.
• What is a soft magnetic material?

  Magnetised when an external magnetic field is applied but are demagnetised when it is removed.
• Name four magnetic materials.

  Iron, cobalt, nickel, steel
• What is a magnetic field?

  A region surrounding a magnet where other magnets will experience a force.
• What direction to magnetic field lines point?

  From north to south.
• High concentration of field lines means the field is…

  strong
• How can you produce a uniform magnetic field?

  By placing opposite poles of two magnets across from each other, you can create a uniform magnetic field where magnetic field lines are separated with a fixed distance.
• How is a plotting compass used to map out a magnetic field?

  On a piece of paper with a magnet, align the compass needle with the magnetic field lines and marking the direction of the needle at different points, a map of the magnetic field can be created by joining the points.
• What must happen for a magnetic field to be created around a wire?

  A current must flow through it.
• Fleming‘s left hand rule, start with Magnetic field (North to South).

  Force (thumb), Magnetic field (index finger), Current (second finger)