Consider the energy levels shown in Figure P3.42. Let $T=300 \mathrm{~K}$. (a) If $E_{1}-E_{F}=$ $0.30 \mathrm{eV}$, determine the probability that an energy state at $E=E_{1}$ is occupied by an electron and the probability that an energy state at $E=E_{2}$ is empty. (b) Repeat part (a) if $E_{F}-E_{2}=0.40 \mathrm{eV}$.