A student uses visible spectrophotometry to determine the concentration of CoCl2(aq) in a sample solution. First the student prepares a set of CoCl2(aq) solutions of known concentration. Then the student uses a spectrophotometer to determine the absorbance of each of the standard solutions at a wavelength of 510nm and constructs a standard curve. Finally, the student determines the absorbance of the sample of unknown concentration.

A wavelength of 510nm corresponds to an approximate frequency of 6×1014s−1. What is the approximate energy of one photon of this light?

9×1047J
3×1017J
5×10−7J
4×10−19J