Chapter Assumptions
Unless stated otherwise, the reference configuration for zero electric potential and zero electric potential energy is one in which there
is infinite separation between charges.
Chapter 24 Problems
Conceptual Problems
C.1 A positively charged particle and a negatively charged particle are located near one another in space. Their masses, the
magnitudes of their charges, and the distance between them are such that their gravitational potential energy equals their
electric potential energy. (The reference configuration for zero gravitational PE, like that for zero electric PE, is an infinite
separation of the particles.) (a) If the distance between the particles is halved, what happens to the electric potential energy of
the configuration? (b) Is the gravitational potential energy of the new configuration still equal to the electric potential energy?
(c) Are they still equal if one of the charges reverses in sign but keeps the same magnitude?
(a) i. It halves
ii. It doubles
iii. It stays the same
(b) Yes No
(c) Yes No
C.2 Explain the difference between electric potential energy and electric potential. How are the two related?C.3 Electric field strength can be measured in N/C, but in view of the equation E = |ǻV/ǻs|, it is often written with the units V/m.
Using only metric units and their definitions, show that 1 N/C = 1 V/m.C.4 (a) Can equipotential surfaces with different electric potentials ever intersect each other? (b) Why or why not? (c) Do any two
equipotential surfaces have to be a constant distance apart? Explain.(a) Yes No
(b)
(c) Yes NoSection Problems
Section 0 - Introduction
0.1 Using the simulation in the first interactive problem in this section, answer the following questions. (a) What is the sign of the
PE? (b) Is the magnitude of the potential energy greater when the test charge is closer to, or farther away from the stationary
charge?(a) i. Always positive
ii. Always negative
iii. Both positive and negative
(b) Closer to Farther away
0.2 Using the simulation in the second interactive problem in this section, answer the following questions. (a) What is the sign of
the PE? (b) As the distance between the charges increases, does the PE increase or decrease? (c) In what type of path
should you move the charge in order to keep its PE constant?
(a) i. Always positive
ii. Always negative
iii. Both positive and negative
(b) i. Increases
ii. Decreases
iii. Stays the same
(c) i. A straight line
ii. A circle
iii. A parabola
iv. A square
0.3 Using the last interactive in this section answer the following questions. (a) How does the potential energy change as you
move the test charge away from the negative plate and toward the positive plate? (b) In what type of path should you move
the test charge in order to keep its PE constant?