Hi all! This week has been jam packed for me, so I have not had the time to continue my discussion of the no-go theorems in quantum information theory. I will save that discussion for the next couple of weeks.

However, I did have some time to create a short post on a physics problem that my students see in their elementary electromagnetism courses. This is a tutorial video that I made for my introductory physics courses showing the derivation of the equilibrium point around two point charges with opposite sign and different magnitudes. I have found that students run into two major pitfalls with this problem:

1. They do not know where the equilibrium point is located relative to the positive and negative charges.
2. They do not take the extra distance between the equilibrium point and the charges into account in their calculations.

Both pitfalls are actually pretty easy to overcome in the classroom. The trick is you simply need to draw a good diagram. As this video shows, once you have a good diagram, the actual calculation is pretty straightforward.

Until next week!