1. (25 pts)
a) (5 pts) Which would have a larger effective capacitance, a 3 µF capacitor in series with a 0.5 µF
capacitor or the same two capacitors connected in parallel?
Connecting in parallel effectively increases the plate area, thus increasing the capacitance.
b) (5 pts) Before applying the principle of superposition to compute the electric potential at some point
due to several pieces of charge, is it necessary to break the electric potential into components? Why or
why not?
Electric potential is a quantity derived from an energy (electric potential energy). Since energy is a
scalar quantity, it has no direction. Thus there is no need for components.
c) (5 pts) You grab three capacitors at random from a junk box and connect them in a serial fashion
and then to a battery. Compare the magnitude of the charges that accumulate on the three capacitors.
When connected in series, each capacitor ends up with the same amount of charge.
d) (5 pts) The electric potential is lower at point athan at point b. In what direction (with respect to
points aand b) does the electric field point?
Since electric fields point in the direction of decreasing electric potential, the field would point from b
(higher potential) to a(lower potential).
e) (5 pts) Under what circumstance(s) can the electric potential energy of a charge decrease as it moves
yet the electric potential at the charge’s position (as it moves) increases?
If ∆Uis negative but ∆Vis positive, this can only mean that the charge involved is negative.
