�EXPERIMENT 14MAGNETIC FIELD MEASUREMENTSI. PURPOSEIn this experiment you will measure the strength of the magnetic field at the center of a current-carrying coil of wire and compare your result to theoretical predictions.II. THEORYThe magnetic field Bat the center of a single circular turn of wire carrying a current Iis(1) where ais the radius of the turn of wire, and n0is the permeability of free space,In the case of a coil of Nturns of the same radius each carrying the same current, the magnetic field is given by(2) A derivation of the relationships above can be found in your textbook.III. APPARATUSThe apparatus consists of a coil of wire mounted so that the plane of the coil is vertical. The mean radius of the coil is 7.60 cm. A horizontal platform extends through the middle of the coil and a magnetic compass is mounted on the platform at the center of the coil. A power supply and an ammeter are also provided. The instructor will explain how to use both the power supply and ammeter.B=μ02aI,μ0=4π×10−7T m/A.B=μ02aNI.