1. The problem statement, all variables and given/known data In a photoelectric experiment, a stopping potential of 2.70 eV is measured when ultraviolet light of wavelength 380 nm is incident on the metal. If blue light of wavelength 440 nm is used, what is the new stopping potential in eV? 2. Relevant equations 3. The attempt at a solution I think i understand how to do this problem (qV = hc/λ - work function) but am very confused as they have given and ask for the stopping potential in eV. I thought that eV was a unit of energy and that stopping potential (as it is a voltage) is given by the units V. How can the units of a potential be eV?