(a) A beam of electrons is incident on a barrier that is 0.60 nm wide and 6.90 ev high. If the number of electrons striking the barrier each second is 6.75 x 1041 /s with an energy of 5.50 ev, then how long would it take for a single electron to be transmitted through the barrier? 2.88*10**14 X If T is the transmission coefficient, how many particles need to strike the barrier before 1 particle can tunnel through? s