What is the E of visible light?

可见光的能量是多少？

麻省理工公开课 - 固态化学导论课程节选

And you have to ask yourself is the energy difference here, the delta E in the electronic states, how does that compare with the E of visible light?

所以我们会问,是由于能量的不同么，例如deltaE在电子能态的不同，那如何把E与可见光联系起来？

麻省理工公开课 - 固态化学导论课程节选