An electromagnet has a steel core (κM≈ 2500) with an approximately circular cross sectional area of 8.0 cm2. The radius of the magnet is 7.0 cm; there is a small air gap of only 3.2 mm (see sketch). The current through the magnet's N= 100-turn coil is 38 A.
What will the magnetic field strength be inside the air gap? Express your answer in Tesla. Assume that the magnetic field is azimuthal (i.e. points around the circle formed by the steel) everywhere and d≪ the radius of the electromagnet.
95 answers