Which statement correctly describes lines of magnetic force extending from a magnet?

Which statement correctly describes lines of magnetic force extending from a magnet?

• A. They extend outward indefinitely into space.
• B. They flow only inside the magnet and stop at the surface.
• C. They have no fixed direction.
• D. Magnetic lines of force form a closed loop called a magnetic circuit.

Answer: (D)

Magnetic field lines always form closed loops; they don’t start or end in empty space because there are no magnetic monopoles. In a magnet, lines leave the north pole, pass through the surrounding space to the south pole, and then inside the magnet they travel from south back to north, completing a continuous loop. This completes what we call a magnetic circuit. That’s why the statement describing lines as forming a closed loop is the best fit. The other ideas would imply lines extend off to infinity, terminate at the surface, or have no fixed direction, which contradicts the way magnetic fields behave.

Magnetic field lines always form closed loops; they don’t start or end in empty space because there are no magnetic monopoles. In a magnet, lines leave the north pole, pass through the surrounding space to the south pole, and then inside the magnet they travel from south back to north, completing a continuous loop. This completes what we call a magnetic circuit. That’s why the statement describing lines as forming a closed loop is the best fit. The other ideas would imply lines extend off to infinity, terminate at the surface, or have no fixed direction, which contradicts the way magnetic fields behave.