1. An electron moves through a region of crossed electric and magnetic fields. The
electric field E = 4000 V/m and is directed straight down. The magnetic field B =
0.80 T and is directed to the left. For w h a t m b f the electron into the paper
will the electric force exactly cancel the magnetic force?
2. A uniform 4.5-T n~agneticfield passes through the plane of a wire loop 0.10 m2 in
area. Whatflux passes through the loop when the direction of the 4.5-T field is at
a 60' angle to the normal of the loop plane?
3. Three resistors connected in series each carry currents labeled 11,I2and 13.Which
of the following expresses the value of the total current ITin the system made up
of the three resistors in series?
4. What is the m i n i m u m t s Q w i t h which a 200-turn, flat coil of cross sectional
area 300 cm2 can be rotated in a uniform 30-mT magnetic field if the maximum
value of the induced emf is to equal 10.5 V?
5. What is the equivalent resistance between points a and b?
6. A solenoid with 500 turns, 0.50 m long, carrying a current of 4.0 A and with a
m will have what strength magnetic field at its center? (magnetic
radius of
T-mlA)
permeability in empty space po = 47r x
g=
/Clo
NI-
7. Two parallel conductors each of 0.50 m length, separated by 5.0 x lo-' m and
carrying 3.0 A in the same direction, will experience what type and magnitude of
T-m/A)
mutual force? (magnetic permeability in empty space po = 4 n x
1'
a.
b.
c.
d.
e.
attractive, 0.06 x
N
repulsive, 0.60 x 1o - N
~
attractive, 1.8 x
N
repulsive, 1.8 x 1o - N
~
zero
/+
8. A circuit contains a 6.0-V battery, a 4.042 resistor, a 0.60-pF capacitor, an
ammeter, and a switch in series. What will be the voltage across the capacitor
long after the switch is closed?
a. zero
b. 0.10V
c. 3.6 V
9. By what factor is the self-inductance of an air solenoid changed if the number of
coil turns is tripled?
10. At what speed v should the bar in the figure be moved to produce a current of 1A
in the resistor? Assume B = 3.00 T into the page, R = 6.0 R and the length of the
bar is 4.50 n ~ .
11. If E = 9.0 V, what is hte-t
+
a. O.1OA
b. 0.15A
L
~
in the 15-R resistor?
J Zz~rl:
d. 0.25 A
e. 0.30 A
/,
1;zX
3Q
=
V
"'.&
p,
U C ~ ~ Sr,Kpc
S
3304- 3
A
-
111
0~3.4
15'61
r7*,*n_
,3i/
in a square loop of wire that
is in the plane of the paper. If the magnetic field B is toward the right, and if each
side of the loop has length L, then the net magnetic torque acting on the loop is:
-+=
b. ILB
e. zero
9u