Cross Product

Consider two vectors, A and B; we can define a new vector C by

C = A x B

Rotate the first vector ( A ) into the second vector ( B ) with the fingers of your right hand. Your thumb then gives the direction of the cross product, A x B.

Remember, C is perpendicular to both A and B.

The magnitude of C is given by

---

F = q v x B

Rotate the first vector ( v ) into the second vector ( B ) with the fingers of your right hand. Your thumb then gives the direction of the cross product, v x B. If the charge is positive, this is the direction of the force. If the charge is negative, the force is in the opposite direction. The magnitude of the force is given by

Force on a Charge			Force on a Current-Carrying Conductor
Return to Ch 29, Magnetic Fields

(c) Doug Davis, 2002; all rights reserved