The cross product of two vectors is often encountered in physics and engineering. In statics and dynamics, you are familiar with the concept of torque and angular momentum. In electricity and magnetism, the force exerted on a moving charged particle when moving in a magnetic field B is given by
The direction of the cross product may be found by application of the right hand rule as follows:
Using your right hand,
Point your index finger in the direction of the first vector.
Point your middle finger in the direction of the second vector.
Your thumb will point in the direction of the cross product.
For example, for a positively-charged particle moving to the North, in a region where the magnetic field points West, the resultant force will point up.
Concept Check: Right Hand Rule
Last updated Sept. 2, 1998.
Copyright George Watson, Univ. of Delaware, 1998.