1. The problem statement, all variables and given/known data A particle of energy E approaches a step barrier of height U0. What should be the ratio E/U0 so that the reflection coefficient is 0.43? 2. Relevant equations R=(k1-k2)^2/(k1+k2)^2 <--------reflection coefficient 3. The attempt at a solution I am completely stumped at how to approach this problem. I cannot find how to get a ratio of E to U0 using any equations. Any help on how to approach this problem is much appreciated.