Physics part 1

I need help answering these

How does the space charge width change with forward and reverse bias? also, calculate the space charge width for a reverse bias of 4v on a silicon pn junction at t = 300k and doping concentrations of na = 5x1015cm-3 , nd = 5x 1016 cm-3 .

Which governments provide garbage collection services to homes and businesses

Two positive charges are equal. which has more electric potential energy?