An electron accelerates across a potential difference of 200 volts. what energy does the electron gain? assuming the electron starts at rest, at what speed is it moving through the potential?

Aresistor with an unknown resistance is connected in parallel to a 9 ω resistor. when both resistors are connected in parallel to an emf source of 21 v, the current through the unknown resistor is measured with an ammeter to be 4 a. what is the resistance of the unknown resistor? answer in units of ω.