California Science Test (CAST) 8th Grade Practice Exam

Electric fields are what allow charges to influence each other at a distance. A charged particle creates an electric field around it, and when another charge sits in that field, it experiences a force. This interaction is called the electrical (electrostatic) force. Its strength and direction follow Coulomb’s law: it depends on how large the charges are and how far apart they are, acting along the line between the charges (repelling if like signs, attracting if opposite signs). Magnetic force would require moving charges or magnetic fields, not just a static electric field. Gravitational force depends on mass, not charge. And centripetal force isn’t a separate kind of force—it’s the inward pull that keeps circular motion going, which could be due to the electrical force in this scenario.