Definition: 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.
Input: This quantity changes the refractive index of a material in the Kerr Effect. It splits spectral lines in the Stark Effect. The product of it and the magnetic field is the Poynting Vector. Its divergence equals charge density over permittivity by Gauss's Law. Equal to charge over (*) radius squared, it is measured in volts per meter. For 10 points, name this vector field symbolized capital E.
Output:
Science