Problem 2.1 Find the current Iand the power supplied by the source in the network shown.
I
6 V
20 k
Ω
Suggested Solution
3
6
0.3 mA
20
10
I
=
=
×
3
(6)(0.3
10
)
1.8 mW
P
VI
−
=
=
×
=

Problem 2.2 In the circuit shown, find the voltage across the current source and the power absorbed by the resistor. 3 mA3 kΩ+VCS_

Problem 2.3 If the 10-resistor in the network shown absorbs 2.5 mW, find V
.
k
Ω
S
V
S
10 k
Ω
Suggested Solution
2
10 k
S
V
P
=
Ω
or
(
)(
)
3
3
2.5
10
10
10
5 V
S
R
−
=
×
=
×
×
=
V
P

Problem 2.4
In the network shown, the power absorbed by
x
R
is 5 mW.
Find
x
R
.
R
x
1
mA
2
Suggested Solution
(
)
3
2
2
3
5
10
20 k
0.5
10
x
P
R
I
−
−
×
=
=
=
Ω
×

Problem 2.5
In the network shown, the power absorbed by
x
R
is 20 mW.
Find
x
R
.
2 mA
R
x
Suggested Solution
(
)
3
2
2
3
20
10
5 k
2
10
P
R
I
−
−
×
=
=
=
Ω
×

Problem 2.6 A model for a standard two D-cell flashlight is shown. Find the power dissipated in the lamp. 1.5 V1.5 V1-ΩlampSuggested Solution 1.51.53 VlampV=+=( )2239 W1lamplamplampVPR===

Problem 2.7 An automobile uses two halogen headlights connected as shown. Determine the power supplied by the battery if each headlight draws 3 A of current.
12 V
Suggested Solution
(
)(
)
12
3
3
72 W
S
P
VI
=
=
+
=

Problem 2.8 Many years ago a string of Christmas tree lights was manufactured in the form shown in (a). Today the lights are manufactured as shown in (b). Is there a good reason for this change?

Problem 2.9 Find 1Iin the network shown.
I
1
12 mA
4 mA
2 mA
Suggested Solution
I
1
12 mA
4 mA
2 mA
I
2
2
0.004
0.002
0.006 A
I
=
+
=
1
2
0.012
I
I
=
+
1
6 mA
I
⇒
=

Problem 2.10
Find
1
I
and
2
I
in the circuit shown.
I
3
= 5 mA
I
S
I
4
= 6 mA
I
1
I
6
= 3 mA
I
2
Suggested Solution
By KCL,
1
4
6 mA
I
I
=
=
Also,
6
2
4
I
I
I
+
=
or
2
0.003
0.006
I
+
=
2
3 mA
I
⇒
=

Problem 2.11
Find
x
I
and
y
I
in the network shown.
4 mA
12 mA
8 mA
I
x
I
y
Suggested Solution
0.012
0.004
x
I
=
+
8 mA
x
I
⇒
=
0.004
0.008
y
I
=
+
4 mA
y
I
⇒
= −

Problem 2.12 Find xI, yIand zIin the circuit shown. IxIyIz2 mA12 mA4 mA

Problem 2.13 Find xIin the circuit shown.

Problem 2.14
Find
x
I
,
y
I
and
z
I
in the network shown.
12 mA
3 mA
2 mA
4 mA
I
x
I
y
I
z
Suggested Solution
12 mA
3 mA
2 mA
4 mA
I
x
I
y
I
z
0.003
0.012
x
I
+
=
9 mA
x
I
⇒
=
0.012
0.002
0.004
y
I
+
+
=
10 mA
y
I
⇒
= −
0.004
0.002
z
I
+
=
2 mA
z
I
⇒
= −

Problem 2.15
Find
x
I
in the circuit shown.
2
I
x
I
x
2 mA
6 mA
Suggested Solution
2
I
x
I
x
2 mA
6 mA
2
0.002
0.006
x
x
I
I
+
=
+
4 mA
x
I
⇒
=