The diagram shows a cycle undergone by a portion of helium gas. Find the efficiency of that cycle.

We received a large number of solutions to our November Challenge Born to turn. We are pleased to recognize the following contributors:

Guidelines for contributors

Many thanks to all contributors and we hope to hear from many more of you in the future!

Note: as always, we would very much appreciate reader-contributed original Challenges.

Boris Korsunsky, Column Editor

AAPT members receive access to The Physics Teacher and the American Journal of Physics as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.