PCS 130 Lecture Notes - Lecture 2: Vacuum Permeability, Cross Product
Document Summary
The source of the magnetic field: moving charges: The magnetic field of a charged particle q moving with velocity v is given by the biot-savart law: ),direction is given bythe hand rule o: 0 is the permeability constant: 4 10 7 t m/a = 1. 275 x 10-6 t m/a. The cross product: cross product is perpendicular to the plane. The magnetic field of the short segment of current is in the direction of s x r. The magnetic field of a long straight wire carrying current i at a distance d from the wire is: 2 )( i d) o direction tangent to a circle around the wire in the right hand. The magnetic field at the centre of a coil of n turns and radius r carrying current i is: Whether it"s a current loop or a permanent magnet, the magnetic field emerges from the north pole.
