1. The problem statement, all variables and given/known data Using the WKB approximation, estimate the lifetime of an electron in the ground state of a 1D quantum well with 10 nm width, surrounded from both sides by 0.3 eV high and 8nm wide barriers. 2. Relevant equations Hint: Estimate the tunneling probability and find the "tunneling attempt frequency" assuming that the electron moves back and forth in the quantum well with the velocity, v = sqr(2E/m) 3. The attempt at a solution This is from a collection of practice questions our professor provided to help us prepare for our final exam. I'm not great at this WKB (semi-classical approximation) method. We are really just looking for the start of this problem since we are having trouble visualizing it. Any help would be much appreciated.