1) An electron that is a certain distance from a proton is acted on by an electrical force.

a) If the electron were moved twice the distance away from the proton, would the electrical force be:

1) 2

2) ½

3) 4

4) ¼

b) If the initial electric Force is, F, and the electron were moved to one third he original distance toward the proton, what would be the new electrical force?

2) What is the magnitude and direction of the electric field at a point 0.75 m away from a point charge of +2.0 pC?

3) Two fixed charges -4.0 C and -5.0 C, are separated a certain distance.

a) Is the net electric field at a location halfway between the two charges:

1) directed toward the -4.0 C charge

2) Zero

3) directed toward the -5.0 C charge

b) If the charges are separated by 20 cm, calculate the magnitude of the net electric field halfway between the two charges.

4) What is the speed of a proton whose kinetic energy is 12.9 keV?

5) An electron is accelerated by a uniform electric field (1000 V/m) pointing vertically upward. Use energy methods to get the magnitude and direction of its velocity after it moves 0.10 cm form rest. Does the electron gain or lose potential energy?

6) How much charge flows through a 12 -V battery when a 2.0 mF capacitor is connected across its terminals?

Problem : Please note the E field is pointing upward. That is key to determining if the the electron is accelerating or decelerating and hence, determining how the KE and PE are changing.