"This course covers topics in Physical Electronics. The sections include:

$5\mathrm{.}1$ Continuity Equations

$5\mathrm{.}2$ Minority Carrier Diffusion Equation

$5\mathrm{.}3$ Quasi$-$Equilibrium and Quasi$-$Fermi Levels

$5\mathrm{.}4$ PN Junction."

Please provide the solution process for the problem in the image.