Right Hand Thumb Rule

The right hand thumb rule finds the direction of the magnetic field produced by a known current direction: hold the current-carrying conductor in the right hand so that the thumb points in the direction of current flow; the fingers, curling around the conductor, then point in the direction of the magnetic field lines produced. The same rule applies to a straight wire and to a circular coil (Figure 3.28), and it is the everyday working tool used throughout the rest of …