So you know that x-rays are higher frequency than UV light, for example, that means it's also higher energy than UV light, and if you think back to our photoelectric effect experiments, do you remember what type of light we were usually using for those? Does anyone remember?

你们知道，X，射线的频率比紫外光高，这意味着，它的能量也比紫外光要高，那么，请大家回想一下我们的光电效应实验，大家还记得当时我们用的是什么光源吗？,有人记得吗？

麻省理工公开课 - 化学原理课程节选

Maybe you can put the frequency of the higher pitches as high so you can detect the sound quicker and That's it exactly.

大概是把频率调到更高的音高后,就能更敏捷地感觉到声音的变化,而那就是原因了

耶鲁公开课 - 聆听音乐课程节选

So this is our final equation, and this is actually called the Balmer series, which was named after Balmer, and this tells us the frequency of any of the lights where we start with an electron in some higher energy level and we drop down to an n final that's equal to 2.

把2代入到这里，所以得到1除以,这就是我们最终的方程，这叫做Balmer系，以Balmer名字命名的,它告诉我们从高能级掉到n等于2的,最终能级所发出光的频率。

麻省理工公开课 - 化学原理课程节选