Magnetic Fields and Permanent Magnets

PHY 201 & 231

Students use computer-integrated probes to measure magnetic fields in real-time from permanent magnets, current carrying wires, coils, and the earth. An automated graphical representation of the field versus time allows rapid observation of magnitude and direction as the probe wand is moved. Students plot magnitude versus distance, 1/d, and 1/d-squared and then consider best-fit curves to infer algebraic relationships between field strength and distance for different sources. Electric current through wire is measured and then used in theoretical calculation of magnetic field for comparison to measured field.

Equipment

Notes

1.) Put out the Extech power supplies. If there are not enough, use the Sargent-Welch power supplies.
2.) Use the bar magnets with hole through center from S75.
3.) Tape 22 gauge solid insulated copper wire down along grid line at one end of graph paper and connect to momentary switch and one D battery.
4.) Momentary switch is made from light bulb SOCKET and a bolt.
5.) Make sure that switch is left open to prevent unnecessary draining of battery.
6.) Connect probes, DC adapter, and computer cable to Labpro interface. (Serial cables for black laptops, USB cables for silver laptops.) Instructor will distribute laptops.