Electrons are fired at a rectangular potential energy barrier, once every 221 ms. If the barrier is 2.55 mm thick and has a height that exceeds the energy of the incident electrons by exactly 637 meV, how long on average would you expect to wait for one electron to pass through the barrier

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final