Member-only story
Lenz’s Law Is Confusing for Many Physics Students — Here’s How It Really Works
In the algebra-based physics course, the second semester gets pretty dicey. There’s a bunch of important things in there — but much of it depends on vector calculus. However, since it’s an algebra-based course the students don’t have the calculus stuff. That means they are left with some equations that might just seem like magic.
The concept that I see students struggle with often is Lenz’s Law. So, I’m going to do my very best to explain how this works and what it does. Don’t worry, I’m not going to use any vector calculus (even though you need that to fully understand the idea).
Faraday’s Law
We need to start with Faraday’s law to get an understanding of Lenz’s law. In short, this says that a changing magnetic field creates an electric field. If that electric field is inside an electrical conductor, you will also get an electric current.
Here we also introduce the idea of magnetic flux. This is like the amount of magnetic field that passes through some surface. It might be easier to think of another flux — like rain flux. Rain flux would be the amount of rain that hits some surface. The rain flux would depend on three things: how hard it’s raining, the size of the area, and the angle between the rain and the area.
