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Name: ______________________
Homework 9
DUE ON MON 12/1
Multiple Choice
Identify the choice that best completes the statement or answers the question.
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1.
The two ends of a 3.0-Ω resistor are connected to a 9.0-V battery. What is the current through
the resistor?
a. 27 A
b. 6.3 A
c. 3.0 A
d. 0.33 A
2. (1 point) When a 24.0-Ω resistor is connected across a 12.0-V battery, a current of 482 mA flows.
What is the internal resistance of the battery?
a. 0.02 Ω
b. 0.9 Ω
c. 25.0 Ω
d. 49.8 Ω
3. (1 point) Resistors of values 6.0Ω, 4.0Ω, 10.0Ω and 7.0Ω are combined as shown. What is the
equivalent resistance for this combination?
(1 point)
a.
b.
c.
d.
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2.3 Ω
3.0 Ω
10.7 Ω
27 Ω
4. (1 point) How much current is flowing in one of the 10-Ω resistors?
a.
b.
c.
d.
0.8 A
2.0 A
1.6 A
2.4 A
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5.
(2 points)
Consider the circuit shown in the figure. What power is dissipated by the entire circuit?
a.
b.
c.
d.
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14 W
28 W
52 W
112 W
6. (2 points) What is the current through the 2-Ω resistor?
a.
b.
c.
d.
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1.0 A
0.50 A
1.5 A
2.0 A
7. (2 points) What is the potential difference between points a and b?
a.
b.
c.
d.
6V
8V
12 V
24 V
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8.
(1 point)
What is the current flowing through the 4-Ω resistor?
a.
b.
c.
d.
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1A
2A
3A
6A
9. (1 point) A 10-V-emf battery is connected in series with the following: a 2-µF capacitor, a 2-Ω resistor,
an ammeter, and a switch, initially open; a voltmeter is connected in parallel across the capacitor. After
the switch has been closed for a relatively long period (several seconds, say), what are the current and
capacitor voltage readings, respectively?
a.
b.
c.
d.
zero A, 10 V
zero A, zero V
5 A, zero V
5 A, 10 V
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10.
A 1 000-V battery, a 3 000-Ω resistor and a 0.50-µF capacitor are connected in series with a
switch. The time constant for such a circuit, designated by the Greek letter, τ, is defined as the time
required to charge the capacitor to 63% of its capacity after the switch is closed. What is the value of
τ for this circuit?
(1 point)
a.
b.
c.
d.
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6.0 × 109 s
1.7 × 10−10 s
1.7 × 10−7 s
1.5 × 10−3 s
11. (2 points) A 1 000-V battery, a 3 000-Ω resistor and a 0.50-µF capacitor are connected in series with a
switch. The time constant for such a circuit, designated by the Greek letter, τ, is defined as the time
that the capacitor takes to charge to 63% of its capacity after the switch is closed. What is the current
in the circuit at a time interval of τ seconds after the switch has been closed?
a.
b.
c.
d.
____
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0.14 A
0.21 A
0.12 A
0.32 A
12. (2 points) A voltage source of 10 V is connected to a series RC circuit where R = 2.0 × 106 Ω, and C =
3.0 µF. Find the amount of time required for the current in the circuit to decay to 5% of its original
value. Hint: This is the same amount of time for the capacitor to reach 95% of its maximum charge.
a. 3.0 s
b. 6.0 s
c. 9.0 s
d. 18 s
13. (2 points) A series RC circuit, which is made from a battery, a switch, a resistor, and a 3.0-µF capacitor,
has a time constant of 9.0 ms. If an additional 6.0-µF is added in series to the 3.0-µF capacitor, what
is the resulting time constant?
a. 4.0 ms
b. 6.0 ms
c. 10 ms
d. This cannot be found without the value of the resistance being given.
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14.
The following three appliances are connected to a 120-V house circuit: i) toaster, 1 200 W, ii)
coffee pot, 750 W, and iii) microwave, 800 W. If all were operated at the same time, what total current
would they draw?
a. 3.0 A
b. 5.0 A
c. 10 A
d. 23 A
15. (1 point) Of the following choices, what is the maximum number of 60-W light bulbs you can connect
in parallel in a 120-V home circuit without tripping the 30-A circuit breaker?
a. 11
b. 35
c. 59
d. 3 600
(1 point)
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