Maybe I shouldn't have started this blog now, not with everything that's been going on.

Now I’m back to technicalities.

For the fifth week of classes in my Electromagnetic Theory class we finally started with the same topics that we had for my Electricity and Magnetism class two terms ago.

There are some differences though. Since in not so many words it is still a review, we will be going through the concepts at twice the speed that we did more than six months ago.

There was the formula for the electrostatic force using the values of two charges and the distance between them.

I gave them immediately an example of a particle in the middle of a square with other particles at half and a fourth of the length of one side. It recalled for them the vectors of the direction of the force, which is towards each other if the charges are opposite in sign and away from each other if the charges are the same in sign.

After getting the magnitude and direction of the forces from the eleven particles, they had to get the x and y components of those forces, add them up then get the resultant force, and its direction.

What I didn’t tell them until after they had practiced again was that if two similar charges are the same distance on opposite sides of a third particle, the forces from them cancel each other out, so that only the force and the direction from one particle remained, and it was along the negative x axis at that.

After that we discussed the electric field, which, again is a whole other chapter in our previous discussions.

But finally, unlike the start of the school year where I had to skim over some topics because some students had not yet taken up integral calculus, this time I don’t have to pull any punches.

Now I could talk about how to get the electric field of a continuous charge distribution, such as a ring, a circular arc and at three different positions relative to a straight conductor.

I even went in depth into the problem solving techniques they could use, such as substituting one variable (like arc length for angle) for another so as to limit the expression inside the integral to constants – particularly useful for the circular arc – and the Pythagorean relationship, for points perpendicular to the symmetry of a charged ring in a two-dimensional plane.

The students, of course, cringed at hearing terms they had been traumatized with so long ago form other teachers like David and Maila, such as “an infinitesimally small region”.

Next time I’ll talk about my latest lecture in Advanced Mathematics. We’re still on the topic of matrices, using elimination methods to solve systems of linear equations I haven’t encountered since my second year in college.

For now, class dismissed.