The incorrect statement about magnetic lines of force is:

(2) Inside the magnet, the lines of force go from north to the south pole of the magnet.

This statement is incorrect because inside the magnet, the lines of force actually form closed loops and do not have a specific direction from north to south. The magnetic field inside a magnet is not a simple unidirectional flow from one pole to the other. Instead, it circulates within the magnet, forming closed loops.

So, the correct answer is (2).