1. The problem statement, all variables and given/known data A particle of mass m is incident on a planar barrier which we represent by a potential [tex]V(z)=\lambda\delta(x)[/tex]. If the energy of the particle is E, and the incident velocity makes an angle [tex]\theta[/tex] with the z axis, what is the probability that the particle will penetrate the barrier? 3. The attempt at a solution I can solve the problem for the case of normal incidence, as this is just the case of a delta potential barrier. However I have no idea how to include the incidence angle in the problem. This is where I am stuck, how/where does the angle [tex]\theta[/tex] come into the setup of the problem?