PROBLEMS
163
S
0.56 k
�
9 V
27 V
2.2 k
�
I
5 V
V
1
+–
1.2 k
�
FIG. 5.79
Problem 9.
120 V
1 k
�
I
V
2
+–
2 k
�
V
3
+–
3 k
�
V
1
+–
R
T
FIG. 5.80
Problem 10.
9.
Determine the current
I
and the voltage
V
1
for the net-
wo
rk of Fig. 5.79.
10.
F
or the circuit of Fig. 5.80:
a.
Find the total resistance, current, and unknown volt-
age drops.
b.
V
erify Kirchhoff’s voltage law around the closed
loop.
c.
Find the power dissipated by each resistor, and note
whether the power delivered is equal to the power dis-
sipated.
d.
If the resistors are available with wattage ratings of
1/2, 1, and 2 W, what minimum wattage rating can be
used for each resistor in this circuit?
11.
Repeat Problem 10 for the circuit of Fig. 5.81.
*12.
Find the unknown quantities in the circuits of Fig. 5.82
using the information provided.
13.
Eight holiday lights are connected in series as shown in
Fig. 5.83.
a.
If the set is connected to a 120-V source, what is the
current through the bulbs if each bulb has an internal
resistance of 28
�
1
8
�
�
?
b.
Determine the power delivered to each bulb.
c.
Calculate the voltage drop across each bulb.
d.
If one bulb burns out (that is, the filament opens),
what is the effect on the remaining bulbs?