This higher tier covers Higher Tier: Magnetic Field Around a Current-Carrying Wire within Magnetic Fields for GCSE Physics. Revise Magnetic Fields in Magnetism for GCSE Physics with 14 exam-style questions and 12 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 10 of 13 in this topic. This section is most useful once the core foundation idea is secure, because it adds the detail that pushes answers higher.
🎓 Higher Tier: Magnetic Field Around a Current-Carrying Wire
The magnetic field around a long straight wire forms concentric circles. The direction follows the right-hand grip rule: point your right thumb in the direction of conventional current (positive to negative); your fingers curl in the direction of the field.
For a solenoid (coil of wire), the field inside is uniform and parallel to the axis — just like a bar magnet. The end where current flows anticlockwise (looking at it) is the north pole; clockwise is south.
Magnetic flux density B: Proportional to current (I) and number of turns per unit length. Adding a soft iron core multiplies B enormously because iron becomes strongly magnetised. B is measured in Tesla (T); 1 T is a very strong field (MRI machines use 1.5–3 T).
Practice questions for Magnetic Fields
What happens when two like magnetic poles (e.g. north and north) are brought close together?
State the rules for the attraction and repulsion of magnetic poles.