1. The problem statement, all variables and given/known data Photons of energy 12 eV are incident on a metal. It is found that current flows from the metal until a stopping potential of 8.0 V is applied. If the wavelength of the incident photons is doubled, what is the maximum kinetic energy of the ejected electrons? 2. Relevant equations I am absolutely clueless. I feel like I'm supposed to use KE = hf - W but how am I supposed to know the frequency if it isn't given? So I don't think I'm supposed to use this one. Please just lead me towards the right direction. I don't have a clue as to which equation to use. 3. The attempt at a solution This question is gibberish to me and I don't know how to even approach it. Please help.