Chapter 5 – Direct-Current Circuit Analysis

Consider a series-connected string of 10 light bulbs, all of which work properly, and all of

which get their power from a single battery. Suddenly one of the bulbs burns out, leaving an open

circuit in its place. What will happen?

(a) All the other bulbs will go out.

(b) The total current drawn from the battery will go up slightly.

(c) The total current drawn from the battery will go down slightly.

(d) The total current drawn from the battery will not change.

A

You connect four resistors in series with a 12.0-V battery: R1 = 47 Ω, R2 = 22 Ω,

R3 = 33 Ω, and R4 = 82 Ω, as shown below. How much current flows through R3?

Schematic 5-1

(a) 0.72 A

(b) 0.36 A

(c) 0.065 A

(d) 0.015 A

C

In the circuit 5-1, how much voltage appears across the series combination of

resistances R 2 and R3?

(a) 7.5 V

(b) 3.6 V

(c) 8.8 V

(d) 12 V

B

In the circuit 5-1, how much power does the series combination of resistances R2 and

R3 dissipate?

(a) 3.6 W

(b) 1.8 W

(c) 0.46 W

(d) 0.23 W

D

In the circuit of 5-1, how much power does R3 dissipate?

(a) 0.14 W

(b) 0.28 W

(c) 1.1 W

(d) 2.2 W

A

Fill in the blanks in the following sentence to make it true: "In a parallel DC circuit

containing a battery and two or more resistors, the ________ any resistor is the same as the

________ any other resistor."

(a) potential difference across

(b) current flowing through

(c) power dissipated by

(d) conductance of

A

Look back at schematic 5-1. Suppose the battery supplies 12.0 V. We don't know any of the

resistance values, but we do know that they're all the same. What's the voltage V2?

(a) 12.0 V

(b) 6.00 V

(c) 4.00 V

(d) 3.00 V.

D

Three resistors are connected in parallel across a 4.5-V battery: R1 = 820 Ω, R2 = 1.5 k,

and R3 = 2.2 k, as shown in Fig. 5-10. How much voltage appears across R2?

(a) 3.0 mV

(b) 1.5 V

(c) 4.5 V

(d) We need more information to calculate it.

C

Schematic 5-2

In the circuit of 5-2, how much current flows through R2?

(a) 3.0 mA

(b) 14 mA

(c) 333 mA

(d) We need more information to calculate it.

A

In the circuit of 5-2, how much power does R2 draw from the battery?

(a) 14 mW

(b) 333 mW

(c) 9.0 μW

(d) We need more information to calculate it.

A

In the circuit of 5-2, how would we calculate the net conductance of the resistor

network?

(a) Add the conductances of the resistors.

(b) Average the conductances of the resistors.

(c) Take the reciprocal of the sum of the conductances of the resistors.

(d) Take the reciprocal of the average of the conductances of the resistors.

A

In the circuit of 5-2, how much energy does the resistor network consume?

(a) 5.5 joules

(b) 9.2 joules

(c) 47 joules

(d) We need more information to figure it out.

D

In the circuit of 5-2, what will happen to the power dissipated by the network as a

whole, if we change the value of R1 from 820 to 8.2 Ω, but leave all the other values alone?

(a) It will decrease a little.

(b) It will decrease a lot.

(c) It will increase a little.

(d) It will increase a lot.

D

Refer back to Fig. 5-5B in the book. Suppose that I3 + I4 + I5 = 250 mA. If I1 = 100 mA,

what's the current I2 through the resistor to the lower right of point Z?

(a) 33 mA

(b) 50 mA

(c) 150 mA

(d) 300 mA

C

Refer to Fig. 5-7 in the book. Suppose that the circuit has 10 resistors in total (n = 10), they all

have values of 100 Ω, and the battery provides 6.3 V. If we double all the resistances to 200 Ω,

what will happen to the voltage at point P2?

(a) It will double.

(b) It will stay the same.

(c) It will get cut in half.

(d) We need more information to figure it out.

B

In the scenario of Fig. 5-7, suppose once more that n = 10 but instead of 100 Ω, the

resistors all have values of 50 Ω. If we double the battery voltage to 12.6 V, in addition to

changing the resistances, what will happen to the voltage at point P2?

(a) It will double.

(b) It will stay the same.

(c) It will get cut in half.

(d) We need more information to figure it out.

A

Imagine four 100-Ω resistors in series, connected to a battery that supplies a voltage

such that the entire network dissipates 4.00 W. How much power does each resistor

consume?

(a) 125 mW

(b) 250 mW

(c) 500 mW

(d) 1.00 W

D

Imagine four 100-Ω resistors in parallel, connected to a battery that supplies a

voltage such that the entire network dissipates 4.00 W. How much power does each resistor

consume?

(a) 125 mW

(b) 250 mW

(c) 500 mW

(d) 1.00 W

D

Imagine four 100-Ω resistors in a 2 × 2 series-parallel matrix, connected to a battery that

supplies a voltage such that the entire network dissipates 4.00 W. How much power does each

resistor consume?

(a) 125 mW

(b) 250 mW

(c) 500 mW

(d) 1.00 W

D

When you design and build a voltage divider network, you should make the resistors' ohmic

values as small as possible without imposing too much current demand on the power supply in

order to:

(a) minimize the effect of external components on the network's behavior.

(b) maximize the voltages at the various points in the network.

(c) minimize the voltages at the various points in the network.

(d) prevent overstressing external components connected to the network.

A