1. The problem statement, all variables and given/known data how many photons (lambda=620*10^-9) must be absorbed to melt 2kg block of ice at 0deg into water at 0deg? and on average, how many H2O molecules does one photon convert from the ice phase to water phase? 2. Relevant equations E=hc/lambda 3. The attempt at a solution I have no idea how to do this? Never done anything like it before! Any hints?