1. The problem statement, all variables and given/known data Estimate the E-field required to ionize Hydrogen in a time comparable to the time taken for the electron to orbit the nucleus. (n=1 ground state) (hint: relate the required E field to the energy of a charged particle) 2. Relevant equations F = mv^2/r (rotational) F = Ze^2/Kr^2 (Coulombic) F = eE (Lorentz) W = F.s ? 3. The attempt at a solution I have calculated the time it takes for the electron to orbit the nucleus T = 1.52 x 10^-16 secs using the rotational force and then solving for v and plugging it in T=2pi r/v with r being Bohr radius. I'm just not sure what else to do? I can get an estimate just just equating the forces and solving for E but that doesn't take into account the time which is specifically asked for? Thanks in advance!