There was a video that generated a lot of buzz online because it featured a popular electromagnetics brainteaser. Simply put, the brainteaser asks: "When you close the switch in a circuit — consisting of a battery, light bulb, and pair of wires — how long will it take for the light bulb to light up?"
However, the more interesting question is: what happens to the signal through the bulb over time? That is a lot more complicated, and to answer that, we can build a model using the COMSOL Multiphysics® software.
In this video, we go over how to set up a model of a long loop of wire connected to a source and a receiver, which are placed 1 meter apart. The model's objective is to compute how long it takes for the receiver to sense when the source is turned on, and to compute the current over time.