# Someone needs to teach Will Shortz about emf

As far as I can tell, quality control for the New York Times crossword puzzle is very good but errors do creep in.

This past Friday, the clue for 37 Across was “Symbol of electromotive force.”  The intended answer: epsilon.  I’ll admit that the symbol for emf looks kind of like an oversized epsilon, but it’s not one: it’s a capital E in a script font.  In over 20 years of doing and teaching physics, I’ve never seen emf denoted by an epsilon.

Oddly enough, the last error I noticed in a Times crossword also had to do with emf.  In that case, the error was more unambiguous.  The clue was “Energy expressed in volts”, which is actually meaningless: volts aren’t a unit of energy.

### Ted Bunn

I am chair of the physics department at the University of Richmond. In addition to teaching a variety of undergraduate physics courses, I work on a variety of research projects in cosmology, the study of the origin, structure, and evolution of the Universe. University of Richmond undergraduates are involved in all aspects of this research. If you want to know more about my research, ask me!

## 7 thoughts on “Someone needs to teach Will Shortz about emf”

1. Huh? Are you saying that the H theorem involves energies expressed in volts? Or that it involves denoting emf with an epsilon?

2. Neither. It’s another case where Greek and Latin letters are sometimes confused. (In this case, in most fonts, they do look completely identical.)

3. Thanks for the explanation! I had never heard that the H in the H theorem was really an eta. I always thought it was an H.

Of course, it’s not clear why Boltzmann would have called entropy H, but then it’s not clear why he would have called it eta either. The word entropy comes from the Greek, but it would start with epsilon, not eta, in that language. Nor is it clear why one would call it S (the usual modern symbol). These things happen when you have only 26 letters to work with.

4. Yeah, the Times Crossword puzzle quality control isn’t what it used to be.

5. Mingshey says:

I am a Physics teacher in Korea. I have just left a rant on the publisher’s website about using epsilon instead of script capital E in Physics textbooks. And I checked out couple of physics textbooks around. Halliday had it okay, but the old PSSC Physics textbooks, the first edition and seventh edition(not Korean translation, but the original English editions), to my horror, used epsilon for the symbol of emf! And they even used lowercase phi(φ) for magnetic flux instead of Uppercase Phi(Φ).