Assignment 4 Solutions
Chpt 26
1. (a) The charge that passes through any cross section is the product of the current and
time. Since t = 4.0 min = (4.0 min)(60 s/min) = 240 s,
q = it = (5.0 A)(240 s) = 1.2 103 C.
(b) The number of electrons N is given by

Assignment 1 Solutions
Chpt 21
6. (a) With a understood to mean the magnitude of acceleration, Newtons second and
third laws lead to
(b) The magnitude of the (only) force on particle 1 is
Inserting the values for m1 and a1 (see part (a) we obtain |q| = 7.

Assignment 3 Solutions
Chpt 24
9. (a) The work done by the electric field is
(b) Since V V0 = W/q0 = z/20, with V0 set to be zero on the sheet, the electric
potential at P is
17. A charge 5q is a distance 2d from P, a charge 5q is a distance d from P, and

Assignment 2 Solutions
Chpt 23
2. We use
and note that the side length of the cube is (3.0 m1.0 m) = 2.0 m.
(a) On the top face of the cube y = 2.0 m and
. Therefore, we have
. Thus the flux is
(b) On the bottom face of the cube y = 0 and
. Therefore, we

Assignment 9 Solutions
Chpt 31
31. (a) The inductive reactance for angular frequency d is given by
, and the
capacitive reactance is given by XC = 1/dC. The two reactances are equal if dL = 1/dC,
or
. The frequency is
(b) The inductive reactance is
XL = d

Assignment 7 Solutions
U
Chpt 29
43. We use Eq. 29-20
for the B-field inside the wire (
17
for that outside the wire (r > a).
(a) At
(b) At
.
,
(c) At
(d) At
) and Eq. 29-
,
,
45. (a) Two of the currents are out of the page and one is into the page, so th

Assignment 8 Solutions
U
Chpt 30
40. Since NB = Li, we obtain
45. (a) Speaking anthropomorphically, the coil wants to fight the changesso if it wants
to push current rightward (when the current is already going rightward) then i must be in
the process of

Assignment 6 Solutions
Chpt 28
38. (a) Using Eq. 28-23 and Eq. 28-18, we find
(b) From
we have
41. (a) The magnetic force on the wire must be upward and have a magnitude equal to the
gravitational force mg on the wire. Since the field and the current are

Assignment 10 Solutions
Chpt 33
36. (a) The fraction of light which is transmitted by the glasses is
(b) Since now the horizontal component of
will pass through the glasses,
49. The angle of incidence for the light ray on mirror B is 90 . So the outgoing

Assignment 11 Solutions
Chpt 37
2. (a) We find from
(b) Similarly,
(c) In this case,
(d) The result is
4. Due to the time-dilation effect, the time between initial and final ages for the daughter
is longer than the four years experienced by her father:
tf