Resumen de Magnetic field of a linear octupole

Enrique Arribas Garde, Isabel Escobar, Raquel Ramírez Vázquez, Arturo C. Marti, Martin Monteiro, Cecilia Stari, Augusto Beléndez

• We measure the magnetic field produced by a linear octupole formed by four magnets placed in such a way that both their magnetic moments and their quadrupole moments cancel each other. The magnetic field is measured with the magnetic sensor of a smartphone together with a suitable app, using the Android operating system. The main objective is to determine the dependence of the x-component of the magnetic field on distance and compare the experimental results with the theoretical result that tells us that this dependence is a quintic decrease.

  Modern smartphones are equipped with various sensors: accelerometer, gyroscope, proximity sensor, ambient light sensor, capacitive sensors, magnetic sensor, GPS, and maybe others.1 The magnetic sensor allows us to measure the magnetic field and works by making use of the classical Hall effect. This magnetic sensor is being used in introductory physics laboratories in interesting ways.1–6