Magnetic fields
ScienceDefinition
A magnetic field is an invisible region around a magnet or moving electric charge where magnetic forces can be detected. Field lines point from the north pole to the south pole outside the magnet. Moving charges and electric currents create magnetic fields, linking electricity and magnetism.
Examples
- Earth's magnetic field deflecting solar wind and enabling compass navigation
- Magnetic field around a current-carrying wire demonstrated by iron filings
- MRI machines using strong magnetic fields to image the body
Key Fact
F = qv × B (force on a moving charge in a magnetic field).
Study This Concept
Practice magnetic fields with free review games in these units: