What to Remember from Lesson 11

11.8. What to Remember from Lesson 11#

Let’s add up all of the new things in this lesson, in a slightly different order from how I introduced them.

  1. Elementary particles often have electrical charges. Electrons are negative, protons are positive, and neutrons have no charge at all, they’re neutral. We would say in our shorthand: \(Q_e = -e\), \(Q_p = +e\), and \(Q_n = 0\).

  2. \(e\) is the fundamental unit of electric charge and has a value of \(e= 1.6 \times 10^{-19}~\)Coulombs. Coulombs are an old unit of electrical charge.

  3. An electric current is electrical charges in motion…usually electrons (not always) and usually in a metal wire (not always). The unit of electrical current is the Ampere and it’s a measure of the amount of charge passing a point in a given time: \(1~\)A \(=1~\)C/s.

  4. A current sets up a magnetic influence in a pattern of circles centered on the current: currents cause magnetism.

  5. Does magnetism cause currents? (Gotcha. That’s for the next lesson.)