a. TRUE - Electric potential, also known as voltage, is measured in units of volts.
b. FALSE - The electric potential at a given location in a circuit is defined the electric potential energy per charge at the location. Its units would be energy units per charge units - a Joule per Coulomb (not simply a Joule).
c. FALSE - The rate at which charge flows past a point is the current. Electric potential is the potential energy per charge at a given location.
d. TRUE - By convention, an electric field is the direction which a positive test charge would be pushed or pulled. If a positive charge is moved against an electric field, then work must be done upon the charge to overcome the opposing effect of the field.
e. FALSE - A positive charge moving in the direction of an electric field is moving without any external help. Such a charge is analogous to a bicycle moving downhill; the bicyclist would not have to pedal. In such instances, there is a loss in electric potential energy, and thus a loss in electric potential.
f. FALSE - Close, but not correct. The difference in electric potential between any two points is simply the different in electric potential energy per charge between those two points. Using a gravitational analogy, gravitational potential is the difference in gravitational potential energy per mass between any two points. Gravitational potential energy is dependent upon the amount of mass present at a location (m•g•h); the more mass present at a location , the more gravitational potential energy. In contrast, gravitational potential reduces the importance of mass by defining itself as the potential energy per kilogram of mass (PE / m). By so doing, gravitational potential is now only location dependent - depending only upon the value of g at a given location and the height above some zero reference level. In the same manner, electric potential energy at a given location is charge-dependent. The more charge present at a location, the more repulsive (or attractive) effects and the greater the potential energy. But electric potential makes the amount of charge unimportant since it is the electric potential energy per charge. Now electric potential is location dependent - dependent for instance on the location in a circuit and not upon the amount of charge flowing past that location in a second.
g. TRUE - Electric potential is the potential energy per charge at a given location. The more electric potential which a unit of charge has at a given location, the more electric potential energy that the charge has.
h. TRUE - In the battery, the positive terminal is the location of high energy and high potential. The negative terminal is the location of low energy and low potential.
i. TRUE - In the battery, a charge is moved from a location of low energy to a location of high energy. The charge would gain electric potential energy and as such, it would also gain electric potential.
j. TRUE - A 6-Volt battery supplies every Coulomb of charge with 6 Joules of energy. The energy per charge ratio is 6 Joules per Coulomb. Thus, 2 Coulombs of charge would gain 12 Joules of energy.