Measuring the local magnetic field Introduction. We are using a single circular wire to investigate the magnetic field produced by an electric current and to estimate the magnitude of the horizontal component of the Earth's magnetic field at that location. Materials. Power supply, conducting circular wire, ammeter, compass, ruler, and connecting wires. Objectives Analyze and interpret experimental data to test theory. Measure the strength of the local magnetic field using the magnetic field produced by the electric current in a circular wire. Background The strength of the magnetic field produced by an electric current I, in a circular wire of radius R, at the center is: Bwire = Hol 2R (1) The direction of Bwe is perpendicular to the plane of the wire, as given by the right-hand rule. This video https://youtu.be/fav3olr-ra0 shows a visualization of the magnetic field produced by a circular loop at various locations (not just at the center). Experiment Part 1. Qualitative observation of the magnetic field produced by a circular current Watch this video: https://youtube/fkovg GOB30 Question: At the 0:12 mark in the video, which of the two alligator dips (left or right) is connected to the positive terminal of the battery? Part 2. Quantitative description of the magnetic field produced by a circular current Running the experiment: https://youtube/fWSm4wgOEXg Highlights The compass is initially aligned with the horizontal component of the Earth's magnetic field. When current is applied, an additional magnetic field is produced. These two fields are perpendicular to each other. The compass needle aligns itself with the sum of the two magnetic field vectors. Indicate the independent (IV), dependent (DV), and control variables (CV) in this experiment: