1. The problem statement, all variables and given/known data The binding energy of an electron to a metal surface is (3.90x10^2) kJ/mol. What is the threshold wavelength (in nm)for the onset of the photoelectric effect? 2. Relevant equations 3. The attempt at a solution work function= 3.9*10^2 kj/mol=6.476103179*10^-19j I know I have to calculate the threshold wavelength of the electron, lambda=h/p and p=mv. mass of an electron is known, and h is a constant, the velocity of the electron is the key to solve this question. I am thinking using "E=hv=(1/2)mu^2+work function" but I don't know "E". Any leads would be great!