Magnetic field lines

Definition

Magnetic field lines are imaginary lines used to represent the direction and strength of a magnetic field. They emanate from the north pole of a magnet and curve around to enter the south pole.

5 Must Know Facts For Your Next Test

1. Magnetic field lines never intersect each other.
2. The density of magnetic field lines indicates the strength of the magnetic field; closer lines mean a stronger field.
3. Inside a magnet, magnetic field lines run from south to north, completing a closed loop.
4. The direction of magnetic field lines at any point gives the direction of the magnetic force on a north pole placed at that point.
5. Magnetic flux through a surface is proportional to the number of magnetic field lines passing through it.

Review Questions

• What does the density of magnetic field lines indicate about the strength of a magnetic field?
• Why do magnetic field lines form closed loops?
• How can you determine the direction of a magnetic force using magnetic field lines?

Related terms

Magnetic Flux: The measure of the total number of magnetic field lines passing through a given area.

Electromagnetic Waves: Waves composed of oscillating electric and magnetic fields, which propagate through space carrying energy.

$\mathbf{B}$-field: \(\mathbf{B}\)-field, or Magnetic Field, is represented by vector $\mathbf{B}$ and describes the influence exerted by magnets or moving charges.