How much resistance is required to limit the current from a 12 V battery to 3.6 mA?

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 .

From center station, a train departs every 30 minutes on the fast line and a train departs every 50 minutes on the state line. if two trains depart from center station at 8: 00 a.m., one on each of the two lines, what is the next time that two trains, one on each line, will depart at the same time?

When considering gravity acceleration and the force of acceleration, what must be true? a. the direction of acceleration must be perpendicular to the direction of the force. b. the direction of the force and the direction of acceleration must be the same as each other. c. the direction of the force and the direction of acceleration must be opposite of each other. d. the mass of the body must be the same as the acceleration of the body.