Which answer would be the least influential for participating in an indoor high-intensity cycling class

The experiments with static charges were done by:

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 type of wave can travel without a medium