PH 122 Lecture Notes - Right-Hand Rule, Electric Dipole Moment, Magnet
Document Summary
Magnetic fields are produced by currents and permanent magnets. The smallest unit is the dipole, as we"ll see. An electric dipole rotates to point along the direction of the electric field. The magnetic field vectors point in the direction of compass needles. We represent the stronger magnetic field near the magnet by longer vectors. The south pole of the earth"s magnet is not at the north geographic pole. Sources of the magnetic field: field of a current-carrying wire. Compasses surrounding the wire needles are tangent to a circle around the wire. When the current direction is reversed, the compass needles turn to point in the opposite direction. Point your right thumb in the direction of the current. Curl your fingers around the wire to indicate a circle. Your fingers point in the direction of the magnetic field lines around the wire. Magnetic field due to a long, straight, current-carrying wire. Sources of the magnetic field: field of a current loop.
