a) An electron moving around the Pi system of a benzene ring is another example of a particle on a ring system. What is the expression for the energy difference between the lowest energy state and the first excited state of the benzene Pi system? Please leave your answer in terms of variables and constants; do not substitute.
b) If the radius of a benzene ring is 120 pm, what is the energy of the lowest energy transition (in units of nm) for benzene?