New some help with some problems. I have tried them an listed what I have done so far... 1. A beam of electrons is sent along the x axis from - with kinetic energy E=7.5eV. The beam encounters a potential barrier of height V'=1eV and width 2a=1.2nm. What fraction of the incident beam is reflected? [Hint: Assume E>>V0] I found k and q and from these found |R|^2, but have had no success in getting the correct answer. Am I supposed to do something after I find |R|^2? 2. Suppose a wave function within a barrier is approximately proportional to e-kx. The probability that a particle will penetrate a barrier of thickness 2a is 0.010. What is the probability of penetrating a barrier that is twice as thick? Not even sure where to start here... I know that my thickness will now be 4a, but what now? 3. Suppose electrons with E= 10.0 eV approach a potential barrier of height 2.0 eV. a. Suppose electrons with E= 10.0 eV approach a potential barrier of height 2.0 eV. in nanometers b. For what minimum barrier thickness is there no reflection? in nanometers Not sure where to start. I think i need to solve for 2aq=n*pi for a and for b where n*pi/2. I am not really looking for the answers, but how to solve them as there is not much help in the text. Thanks in advance.