Which one of the following statements about magnetic field lines is NOT correct ?

Magnetic field lines are continuous, closed loops that exist both outside and inside a magnet. While they travel from the north pole to the south pole outside the magnet, they travel from the south pole to the north pole inside the magnet [1]. Therefore, the statement that there are no field lines within a bar magnet is incorrect. Regarding other options, magnetic field lines can emanate from a point source (like a magnetic monopole, though theoretically debated, or a point-like pole approximation). They never cross each other because the magnetic field at any point must have a unique direction; an intersection would imply two different directions at one point [1]. Finally, field lines between two poles are generally curved and cannot be precisely straight at the ends due to the divergence of the field as it exits the pole faces [2].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 12: Magnetic Effects of Electric Current > Activity 12.3 > p. 197
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 12: Magnetic Effects of Electric Current > 12.2.4 Magnetic Field due to a Current in a Solenoid > p. 201