Suppose we put two charged beads (point charges) on a taut string, some distance
ID: 1525204 • Letter: S
Question
Suppose we put two charged beads (point charges) on a taut string, some distance apart, but fixed in place (immovable). One bead's charge is positive, the other bead's charge is negative, and the charges' magnitudes are unequal. No other charges are nearby these two, and we'll let the string serve as the x axis. Now choose some position A on the string, other than the positions of the beads. Position A should not be the midpoint between the beads, but any other position on the same axis is fine. Question: if you reversed only the sign of one of the two bead's charges, would the net electric field at A increase, decrease, or remain the same? What about the net electric potential?
Explanation / Answer
as electric field is directional and direction depends upon sign of the charge, reversing sign of one charge will reverse the direction of field and it may increase or decrease the net electric field depending upon position of A.
as electric potential is a scalar quantity and directly proportional to the charge (with sign included), by making both charges of same sign, magnitude of potential will increase.