Unformatted text preview: Electrical Potentials Electrical Potentials -- Conceptual Solutions 1.) What does an absolute electrical potential actually tell you? That is: a.) Is it a vector? If so, what does its direction signify?
Solution: Electrical potentials are modiﬁed potential energy functions. As such,
they are scalar ﬁelds and have no direction associated with them. b.) What does its magnitude tell you?
Solution: If you know the absolute electrical potential at a particular point in an
electric ﬁeld, you know how much potential energy per unit charge is available at
that point due to the presence of the ﬁeld. That is, electrical potentials are modiﬁed potential energy functions. (Note that electrical potentials are often
referred to simply as potentials.) c.) How are electrical potentials used in everyday life?
Solution: Electrical potential diﬁ'erences and electric fields go hand in hand.
That is, if you create an electrical potential difference between two points, you
will also have created an electric ﬁeld between those two points (and vice versa).
That means that when you switch a lamp on in your home, the electric ﬁeld that
motivates current to ﬂow through the lamp's light bulb is actually being produced by an artiﬁcially created electrical potential difference between the two prongs of
the lamp's electrical cord. 2.) An electrical potential ﬁeld is oriented so that it becomes larger as you
move to the right. a.) What will a positive charge do if put in the ﬁeld?
ﬁglutign: Positive charge "falls" through potential differences proceeding from
higher to lower electrical potentials. In this case, that means they will accelerate to the left. b.) What will a negative charge do if put in the ﬁeld?
5311131911: Negative charge does the opposite of positive charge, so they will
accelerate from lower to higher electrical potential. In this case, that will be to the
right. c.) Is there an electric ﬁeld associated with the 10W“ V potential and, if so, in what direction is it oriented?
ﬁolution: By deﬁnition, the direction of an electric ﬁeld is the direction a positive charge would E .hlghcrv
accelerate if put in the ﬁeld. As positive charge moves
from higher to lower electrical potentials, electric
ﬁeld lines must be oriented from higher to lower
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- Spring '11