A technician checks a labelled permanent magnet before it is fitted inside a loudspeaker. A plotting compass has produced a trail of pencil dots outside the magnet, linking its poles labelled N and S. The final dot has been marked.
What should the technician do next to complete the field-line record?
Join the dots with straight sections and add arrowheads pointing from N towards S.
Join the dots with one smooth curve and add arrowheads pointing from S towards N.
Join the dots with one smooth curve and add arrowheads pointing from N towards S.
Join the dots with straight sections and add arrowheads pointing from S towards N.