Final answer:
When electrons are allowed to flow after building up a charge, it is an example of current electricity, which is essential for powering various technological devices and is a fundamental concept in the study of electromagnetic phenomena.
Step-by-step explanation:
When electrons build up a large charge and then the charge "lets go" causing the electrons to start flowing, we are discussing a phenomenon known as current electricity. This is different from static electricity where charges accumulate on an object's surface and stay relatively still until they find a way to discharge quickly, for instance through a spark. In current electricity, the flow of electrons through a conductor, such as a wire, is steady and directed, making it a fundamental concept in electromagnetic phenomena. An example of this can be highlighted by the Hall effect, where charges moving through a conductor in a magnetic field create a voltage across the conductor due to the force exerted by the magnetic field on the moving charges.
The situation you described aligns with current electricity, which is essential in countless applications, from powering handheld calculators to sending energy to homes and businesses. Although we encounter many devices that use current electricity daily, the details of how charged particles move and interact with magnetic fields are grounded in complex physical principles discussed in physics.