A modification of the Oersted experiment

The paper describes a simple set-up of the Oersted experiment. A planar coil of wires has been used to deflect vigorously the magnetic needle (more than 80 angular degrees) when a current of up to 1 A flows along it. Based on theoretical analysis the torque on the magnetic field is analytically expressed taking into account the inhomogeneity of the field and the needle shape. This modification of the Oersted experiment can be used as an easily-made and low-cost set-up or a laboratory workshop at the undergraduate level. Moreover, a procedure to measure the Earth's magnetic component is implied and implemented and its magnitude has been estimated following the same steps. (Contains 2 footnotes and 7 figures.)