Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

In 1878 Henry Rowland showed that this could be produced by spinning a vulcanite plate sandwiched between two glass plates. Zeeman showed that it could split spectral lines, useful in electron paramagnetic resonance spectroscopy, and a voltage difference is created by it applied perpendicularly to an electron flow in a conductor in what as known as the Hall effect. Purcell pedagogically described it as the relativistic side effect of electrons moving near one another, and the force on a moving charged particle is calculated by taking the cross product of the velocity and it. For 10 points, identify this field produced by a moving charge or a changing electric field measured in Tesla.
Science