Figure 4.1 A typical ﬂ ux pattern around a bar magnet. The arrows indicate the direction that a compass needle would point to at that position in the ﬁ eld
These forces exist and can be detected without any physical contact between the magnet and the iron ﬁ lings. The general name for a force of such a type is a fi eld force. The ﬂ ux pattern, therefore, is a map of the magnetic fi eld of the magnet, and it indicates the direction and strength of this ﬁ eld.