Download Giambattista, Ch. 17 4, 10, 14, 17, 21, 28, 31, 33, 37, 40

Giambattista, Ch. 17 4, 10, 14, 17, 21, 28, 31, 33, 37, 40, 52, 57 4.Strategy The work done by the external agent is positive since the potential energy increases. Use Eq. (17-1).
Solution Find the work done by the external agent.
10. Strategy Use the principle of superposition and Eq. (17-9).
Solution Sum the electric fields at the center due to each charge.
Do the same for the potential at the center.
14. Strategy Just outside the surface of the sphere, the electric potential is given by
radius of the sphere.
Solution Find the electric potential.
17. Strategy Use Eq. (17-9).
Solution Find the electric potential at the third corner, B.
21. Strategy Rewrite each unit in terms of kg, m, s, and C.
Solution Show that
and
therefore
where r is the
28. (a)Strategy Equipotential surfaces are perpendicular to electric field lines at all points. For equipotential
surfaces drawn such that the potential difference between adjacent surfaces is constant, the surfaces are closer
together where the field is stronger. The electric field always points in the direction of maximum potential
decrease.
Solution The electric field lines are radial. They begin on the point charge and end on the inner surface of
the shell. Then they begin again on the surface and extend to infinity.
(b) Strategy Use Eqs. (16-5) and (17-8), and the principle of superposition.
Solution For
E is that due to the point charge,
conductor. For
For
E once again is that due to the point charge,
charge). For
since this is inside a
For
(point
since V is continuous, and it is constant in a conductor. For
(to preserve continuity).
31.Strategy Use conservation of energy and Eq. (17-7).
Solution Find the change in kinetic energy.
33.(a) Strategy The electric field always points in the direction of maximum potential decrease. Electrons, being
negatively charged, move in the direction opposite the direction of the electric field; that is, in the
direction of potential increase.
Solution Since the speed of the electron decreased, it must have traveled in the direction of the electric
field, so it moved in the direction of potential decrease; that is,
(b) Strategy The kinetic energy of the electron decreased, so its potential energy increased. Use
conservation of energy and Eq. (17-7).
Solution Compute the potential difference the electron moved through.
37. Strategy and Solution
(a) Electrons travel opposite the direction of the electric field, so
(b) For a uniform electric field,
so
(c) Since the electron gains kinetic energy, its potential energy
is directed
Thus,
40.(a) Strategy Use Eq. (17-10).
Solution Compute the maximum potential difference across the capacitor.
(b) Strategy Use the definition of capacitance, Eq. (17-14).
Solution Compute the magnitude of the greatest charge.
52.Strategy Use the definition of capacitance, Eq. (17-14).
Solution Compute the capacitance of the capacitor.
57.(a) Strategy Use Eq. (17-18c).
Solution Compute the capacitance.
(b) Strategy Use Eq. (17-18a).
Solution Compute the potential difference.