Right Hand Rule

Study Helps Here

The right hand rule tells you the direction a magnetic field (B) will move an already moving charge.

Your right hand needs to be open, with your thumb pointing at 90 degrees to your fingers.

The fingers point in the direction of the magnetic field (which always points from the north pole of a magnet to the south pole).

The thumb points in the direction a positive charge is moving. These charges could be a single charge, a bunch of charges (known as current, I), or a wire being pushed (a wire has charges in it, so moving a wire moves the charges in the wire). All of these examples are all v (thumb).

The palm points in the direction the magnetic field moves the charge. This is the Fmag, or magnetic force. Fmag MUST BE the direction B moves the charge (or wire) NOT an external force. A current flowing in a wire, due to an external voltage supply is not Fmag; it is the direction of v (moving charges). However, the direction the current carrying wire moves due to B IS Fmag (your palm). Also, when a wire is moved into B, the charges in the wire (q) move due to B, causing an induced current in the wire (Fmag).

Two notes: 1) If the charge isn't moving, there is no Fmag. 2) The Right Hand Rule works only for positive charges (protons and conventional current, which flows from positive to negative). If you are asked to find Fmag for an electron or negative current, use your left hand.