And if it is going to be a standing wave then this must be an integral number of wavelengths.

如果这有个驻波的话,那么周长就是个整数。

麻省理工公开课 - 固态化学导论课程节选

I have to have a whole number of wavelengths to get around the circumference.

我必须要有个关于波长的总体数字,测量周长。

麻省理工公开课 - 固态化学导论课程节选

r So the circumference is 2 pi r.

周长=2π

麻省理工公开课 - 固态化学导论课程节选