The incorrect statement regarding the lines of force of the magnetic field B is:
A) magnetic intensity is a measure of lines of force passing through a unit area held normal to it.
B) magnetic lines of force form a closed curve.
C) inside a magnet, its magnetic lines of force move from the north pole of a magnet towards its south pole.
D) magnetic lines of force never cut each other.

Hint:
The lines of magnetic force points to the region where the force of magnet can be experienced. It is found that with increasing distance between magnetic poles the density of magnetic lines also decreases. The direction of magnetic field lines outside the magnet from north pole to south pole.




Complete step by step solution:


Magnetic field lines are closed curves, we all know that. Outside the magnet the line is from north to south and inside the magnet it is opposite.so it is also true.

We just discuss in the above paragraph that inside the magnet magnetic field lines are from south to north pole. Hence it is a wrong statement. Therefore, we got our answer.
Hence the correct option is C.



Therefore, the correct option is C.




Note:
An important property regarding magnetic lines of force is that at any point magnetic lines do not intersect each other. This is because magnetic dipoles create non-intersecting sets of magnetic field lines around them and the point of intersection, the magnetic field has more than one direction at any point. But in reality they have a specific direction.