Science — CBSE Class 10 board question

Magnetic field lines are curved paths along which a hypothetical free north pole would tend to move in a magnetic field.

Two properties:

1. Magnetic field lines emerge from the north pole and merge at the south pole; inside the magnet they run from south to north — thus they are closed curves.
2. No two field lines intersect each other, because at any point the magnetic field can have only one direction.

Source: Chapter 12, Section 12.1 — Magnetic Field and Field Lines

---

• The definition must mention the "hypothetical free north pole" — this is the standard NCERT phrasing examiners expect.
• For the two properties, the most commonly tested ones are: (i) closed curves (north → south outside; south → north inside) and (ii) no intersection. Mentioning why they don't intersect (only one direction at a point) earns full credit and shows understanding.
• Do not list more than two properties — the question asks for exactly two.