So that means we're going to need to figure out what is the energy per photon that's emitted by that UV light.

所以那意味着我们将需要,计算出从紫外光源发射出的,每个光子的能量。

麻省理工公开课 - 化学原理课程节选

And sometimes it's a matter of factors that you need to figure out what it is, and maybe it's that there's extra light in the room we don't know about.

而且有时候它是,需要计算的一个因素，有时候这个房间里可能有,我们未知的额外的光。

麻省理工公开课 - 化学原理课程节选