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Copyright ©2015, Elsevier, Inc
Solution Manual Chapter 10: Electrical Engineering
If no circuit sketch is already given, it is highly recommended you first draw each circuit
to answer these problems. It is generally useful to notate your diagram with what you
think you know, such as voltages and currents at each point.
Note the equivalence among these electrical units:
[Ω] = [V]/[A], [W] = [V][A] = [Ω][A]2 = [V]2/[Ω]
The circuits for Exercises 10.1–10.8 are given in the figure.
2
10-1) For the circuit shown, find the voltage V.
Need: Voltage = _____ V
Copyright ©2015, Elsevier, Inc
10-2) For the circuit shown, find the current I.
Need: Current = ____ A
Know: V = 12 V across a 100. Ω
resistor
100
.
Ω
I
Copyright ©2015, Elsevier, Inc
10-3) For the circuit shown, find the resistance R.
R
Need: Resistance = ____ Ω
Know: I = 1.5 A through resistor driven by 12 V.
12
V
I
=
1.5 A
10-4) For the circuit shown, a power of 100. watts is dissipated in the resistor. Find the
current I.
R
Need: Current = ____ A
Know: P = 100. W; V = 12 V
12
V
I
10-5) For the circuit shown, a power of 100. watts is dissipated in the resistor. Find the
resistance, R.
R
Need: Resistance = ____ Ω
Know: P = 100. W and I = 50. A
V
I
=
50. A
10-6) For the circuit shown, find the current I.
I 100.Ω
Need: Current,
I = ____ A
Know: Each parallel resistor is 100. Ω with a 12 volt drop across it
12
V
I
1
I
2
Copyright ©2015, Elsevier, Inc
10-7) For the circuit shown, find the voltage V.
100.Ω
Need: Voltage = ____ V
Know: Total current is 4.0 A so that I = 4.0 A = I1 + I2 through the two parallel
legs.
I = 4.0 A
V
I
1
I
2
Copyright ©2015, Elsevier, Inc
10-8) For the circuit shown, find the resistance R.
I = 0.10 A 100.Ω R
Need: Resistance, R = ____ Ω
Know: Total current = 0.10 A, R1 = 100. Ω with voltage drop of 9.0 V.
10-9) For the circuit shown, a power of 100. watts is dissipated in each resistor. Find the
current I and the voltage V.
60.Ω
Know: P = 100. W in each 60.Ω resistor.
I
1
I
I
V
I
1
I
2
Need
Current
:
I
= ____ A and
V
= ____ V.
Copyright ©2015, Elsevier, Inc
10-10) A circuit consists of a 3.0 V battery and two resistors connected in series with it. The
Need: Current = _____ A
Know: Voltage drop overall = 3.0 V; series resistors of 10. and 15 Ω
respectively.
+
-
I
V
=
3.0 V
V
0.V
=
R
1
= 10.
Ω
R
2
15
=
Ω
V
3.
0
V
=
10-11) A circuit consists of a 12 V battery and a resistor connected in series with it. The
current is 105 A. Find the resistance.
V= 12. V R
V = 0.V
Need: R = ____Ω
Know: Voltage drop is 12 V; current through resistor is 105 A.
+
-
I = 105 A
V
=
12
V
13
10-
a 1500 Ω resistor and the other containing a 1.0 × 103 Ω resistor. Find the current drawn
from the battery.
V = 9.0 V
V = 0. V
Need: Current, I = _____ A.
Know: Parallel circuit with 1500 and 1.0 × 103 Ω resistors with 9.0 V
across each leg.
10-13) A circuit consists of a 12 volt battery attached to a 1.0 × 102 Ω resistor, which is
in turn connected to two parallel branches, each containing a 1.0 × 103 Ω resistor. Find
the current drawn from the battery.
Need: Current, I= _____A
Know: Parallel/series circuit with 2 by 1.0 × 103 Ω resistors in parallel and
a 1.0 × 102 Ω resistor in series. Total circuit voltage drop is 12 volts.
1.
0
×
10
3
Ω
I
V
=
12
V
I
1
I
2
1.0
×
10
2
.
Ω
V
=
0
12
V
V?
1.
0
×
10
3
Ω
10-14) An automobile’s 12 V battery is used to drive a starter motor, which for several
seconds draws a power of 3.0 kW from the battery. If the motor can be modeled by a
single resistor, what is the current while the motor is operating?
R
12
V
I
V
12 V
=
V
=
0. V
10-15) An automobile’s 12 V battery is used to light the automobile’s two headlights.
Each headlight can be modeled as a 1.00 Ω resistor. If the two headlights are hooked up
to the battery in series to form a circuit, what is the power produced in each headlight?
Why would you not wire car lights in series?
V = 0.V
Need: Power = ____ W
+
-
I
R
2
1.
00
=
Ω
V
12
V
=
10-16) An automobile’s 12 V battery is used to light the automobile’s two
headlights. Each headlight can be modeled as a 1.00 Ω resistor. If the two
headlights are hooked up to the battery in parallel to form a circuit, what is the
power produced in each headlight? Why is a parallel circuit preferred for this
application?
Need: Power = ____ W
Know: Parallel circuit with 2 by 1.00 Ω lights and a 12 V battery
1.0
Ω
I
V
12
I
1
I
2
V
=
12 V
V
=
0. V
1.0
Ω
