1. The problem statement, all variables and given/known data Suppose that an STM scans a surface at a distance of a=1.000nm. Take the height of the potential barrier to be U°-E=2.00 eV. If the STM tip movies away from the surface by 2.00%, estimate the percentage change in the tunneling current. 2. Relevant equations 3. The attempt at a solution I honestly dont know how to do this. Ive been reading over our chapter on tunnelling and there doesnt seem to be anything related to this problem.