8-MAGNETIC dipole


Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 26 MAGNETIC FIELDS AND THE MAGNETIC DIPOLE OBJECT To get the magnetic dipole two ways: plot the magnetic field vs. 1/r 3 and to plot the frequency squared (w^2) in a magnetic field vs. that magnetic field. ( It is extremely important to use SI units in this lab. Use meters, amperes and Tesla as your units of distance, current and magnetic field .) APPARATUS Ring magnet; helmholtz coil, power supply, string, ruler, magnetic field sensor, datastudio software, interface box, rod on tripod, cross connector, cross rod from photogate platform THEORY The magnetic field of a ring magnet is similar to that produced by a pair of unlike electrical point charges (an electric dipole); however, no such thing as a “magnetic charge” exists in nature. Instead, magnetic fields may be described only in terms of a dipole. It is as if “magnetic charges” (or poles) exist only in pairs. It may be shown mathematically that the magnetic field produced by a dipole at any point along a line intersecting the dipole, and measured parallel to it is given exactly by: ( ) 2 3 2 2 2 ) ( z R z B z + = μ π μ , where 2 2 1 R R R + = Eq. 1) Figure 1) The magnetic field of a circular magnet is shown. The dipole moment and the magnetic field on the z axis are indicated. The inner and outer radii of the ring magnet are R 1 and R 2 . μ B z 27 The dipole moment also determines the movement of the magnet in an applied field. The torque on a dipole in a magnetic field is α μ τ I B e − = × = v v v , E q . 2 ) where I is the moment of inertia, B e is the external field and α is the angular acceleration. This becomes the approximate differential equation for small angles of deflection,...
View Full Document

This note was uploaded on 08/25/2011 for the course PHYS 164 taught by Professor Johnjames during the Fall '09 term at MO St. Louis.

Page1 / 4


This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online