Which of the following is false about the magnetic field lines?

The correct answer is Option (4) → Both (1) and (3)

The tangent to a magnetic field line at a point gives the direction of \( \vec{B} \) there. The number of lines crossing unit area shows how strong the field is.

Option (1) They intersect each other. — False. At a crossing point there would be two tangents, that is, two directions of \( \vec{B} \). But the field at a point has a unique direction. Statement (3) is also false, so this option alone is incomplete.

Option (2) They never intersect each other. — True. This is the correct property of field lines. The field direction at every point is unique.

Option (3) They are denser away from the poles. — False. The field of a bar magnet is strongest at the poles and weakest in the middle region. So the lines are crowded near the poles and spread out away from them. Statement (1) is also false, so this option alone is incomplete.

Option (4) Both (1) and (3) — Both false. Field lines do not intersect, so (1) is false. They are densest near the poles, where the field is strongest, so (3) is false.

NCERT (2026-27):
The Magnetic Field Lines – “(iii) The larger the number of field lines crossing per unit area, the stronger is the magnitude of the magnetic field B.”

The Magnetic Field Lines – “(iv) The magnetic field lines do not intersect, for if they did, the direction of the magnetic field would not be unique at the point of intersection.”

Example 5.1 – “… In a bar magnet the intensity of the magnetic field is the strongest at the two ends (poles) and weakest at the central region.”