Name: 
 

Chapter 17 Review


Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
When a positive charge moves in the direction of the electric field, what happens to the electrical potential energy associated with the charge?
a.
It increases.
b.
It decreases.
c.
It remains the same.
d.
It sharply increases, and then decreases.
 

 2. 
Charge buildup between the plates of a capacitor stops when
a.
there is no net charge on the plates.
b.
unequal amounts of charge accumulate on the plates.
c.
the potential difference between the plates is equal to the applied potential difference.
d.
the charge on both plates is the same.
 

 3. 
When a capacitor discharges,
a.
it must be attached to a battery.
b.
charges move through the circuit from one plate to the other until both plates are uncharged.
c.
charges move from one plate to the other until equal and opposite charges accumulate on the two plates.
d.
it cannot be connected to a material that conducts.
 

 4. 
What effect will be produced on a capacitor if the separation between the plates is increased?
a.
It will increase the charge.
c.
It will increase the capacitance.
b.
It will decrease the charge.
d.
It will decrease the capacitance.
 

 5. 
Increasing the potential difference between the plates of a capacitor will produce what effect on the capacitor?
a.
It will increase the charge on each plate.
b.
It will decrease the charge on each plate.
c.
It will increase the capacitance.
d.
It will decrease the capacitance.
 

 6. 
A 0.25 mF capacitor is connected to a 9.0 V battery. What is the charge on the capacitor?
a.
1.2 ´ 10mc006-3.jpg C
c.
2.5 ´ 10mc006-5.jpg C
b.
2.2 ´ 10mc006-4.jpg C
d.
2.8 ´ 10mc006-6.jpg C
 

 7. 
A parallel-plate capacitor has a capacitance of C F. If the area of the plates is doubled while the distance between the plates is halved, the new capacitance will be
a.
4C.
c.
mc007-1.jpg.
b.
2C.
d.
mc007-2.jpg.
 

 8. 
A 1.5 mF capacitor is connected to a 9.0 V battery. Use the expression PE = mc008-1.jpgC(DV)mc008-2.jpg to determine how much energy is stored in the capacitor.
a.
1.1 ´ 10mc008-5.jpg J
c.
6.1 ´ 10mc008-7.jpg J
b.
6.1 ´ 10mc008-6.jpg J
d.
60.8 J
 

 9. 
How is current affected if the time interval over which the charge passes through a given area decreases while the amount of charge remains the same?
a.
The current increases.
b.
The current decreases.
c.
The current initially increases and then is gradually restored.
d.
The current is not affected.
 

 10. 
The current in an electron beam in a cathode-ray tube is 7.0 ´ 10mc010-1.jpg A. How much charge hits the screen in 5.0 s?
a.
2.8 ´ 10mc010-4.jpg C
c.
3.5 ´ 10mc010-6.jpg C
b.
5.6 ´ 10mc010-5.jpg C
d.
5.3 ´ 10mc010-7.jpg C
 

 11. 
When electrons move through a metal conductor,
a.
they move in a straight line through the conductor.
b.
they move in zigzag patterns because of repeated collisions with the vibrating metal atoms.
c.
the temperature of the conductor decreases.
d.
they move at the speed of light in a vacuum.
 

 12. 
A lightbulb has a resistance of 240 W when operating at 120 V. What is the current in the lightbulb?
a.
2.0 A
c.
0.50 A
b.
1.0 A
d.
0.20 A
 

 13. 
Which of the following does not affect a material’s resistance?
a.
the length of the material
c.
the temperature of the material
b.
the type of material
d.
Ohm’s law
 

 14. 
Which of the following wires would have the greatest resistance?
a.
an aluminum wire 10 cm in length and 3 cm in diameter
b.
an aluminum wire 5 cm in length and 3 cm in diameter
c.
an aluminum wire 10 cm in length and 5 cm in diameter
d.
an aluminum wire 5 cm in length and 5 cm in diameter
 

 15. 
Which of the following wires would have the least resistance?
a.
a copper wire 10 cm in length at 32°C
b.
a copper wire 5 cm in length at 32°C
c.
a copper wire 10 cm in length at 10°C
d.
a copper wire 5 cm in length at 10°C
 

 16. 
The power ratings on lightbulbs are measures of the
a.
rate that they give off heat and light.
b.
voltage they require.
c.
density of the charge carriers.
d.
amount of negative charge passing through them.
 

 17. 
When compared in a given time interval with other lightbulbs connected to a 120 V circuit, a 60 W lightbulb
a.
converts the same electrical energy to heat and light as a 40 W lightbulb.
b.
converts more electrical energy to heat and light than a 100 W lightbulb.
c.
converts less electrical energy to heat and light than a 40 W lightbulb.
d.
converts less electrical energy to heat and light than a 100 W lightbulb.
 

 18. 
Which set of information will allow you to calculate the kilowatt•hr usage?
a.
the voltage and current in the circuit
b.
the resistance, the current, and the time the circuit operates
c.
the voltage and the resistance of the circuit
d.
the current and the time the circuit operates
 

 19. 
If a 75 W lightbulb operates at a voltage of 120 V, what is the current in the bulb?
a.
0.62 A
c.
1.95 ´ 10mc019-2.jpg A
b.
1.6 A
d.
9.0 ´ 10mc019-3.jpg A
 

 20. 
Tripling the current in a circuit with constant resistance has the effect of changing the power by what factor?
a.
mc020-1.jpg
c.
3
b.
mc020-2.jpg
d.
9
 

 21. 
If the current through a 5.00 ´ 10mc021-1.jpg W heater is 4.00 A, what is the potential difference across the ends of the heating element?
a.
2.00 ´ 10mc021-4.jpg V
c.
2.50 ´ 10mc021-6.jpg V
b.
1.25 ´ 10mc021-5.jpg V
d.
8.00 ´ 10mc021-7.jpg V
 

 22. 
If a 325 W heater has a current of 6.0 A, what is the resistance of the heating element?
a.
88 W
c.
9.0 W
b.
54 W
d.
4.5 W
 

 23. 
An electric toaster requires 1100 W at 110 V. What is the resistance of the heating coil?
a.
3.3 W
c.
10 W
b.
9.0 W
d.
11 W
 

 24. 
Which process will double the power dissipated by a resistor?
a.
doubling the current while doubling the resistance
b.
doubling the current and making the resistance half as big
c.
doubling the current and doubling the potential difference
d.
doubling the current while making the potential difference half as big
 

 25. 
A color TV draws about 2.5 A when it is connected to a 120 V outlet. Assuming electrical energy costs $0.060 per kW·h, what is the cost of running the TV for exactly 8 h?
a.
$0.014
c.
$0.14
b.
$0.03
d.
$0.30
 

Short Answer
 

 26. 
What is electrical potential energy?
 

 27. 
What is electric potential?
 

 28. 
What is potential difference?
 

 29. 
What is capacitance?
 

 30. 
How does a capacitor store energy?
 

 31. 
The spacing between the plates of a particular capacitor is reduced from 1.5 ´ 10sa031-1.jpg cm to 1.5 ´ 10sa031-2.jpg cm. How will this spacing change affect the capacitor?
 

 32. 
How does a dielectric increase the capacitance of a capacitor?
 

 33. 
What is electric current?
 

 34. 
What is the SI unit for current?
 

 35. 
With regard to the flow of electric current, what is resistance?
 

 36. 
What is an ohmic material?
 

 37. 
What are the characteristics of direct current?
 

Problem
 

 38. 
When an electron (q = –1.6 ´ 10pr038-1.jpg C) moves 0.10 m along the direction of an electric field with a strength of 3.0 N/C, what is the magnitude of the potential difference between the electron’s initial and final points?
 

 39. 
What is the capacitance of a parallel-plate capacitor made of two square aluminum plates that are 4.0 cm in length on each side and are separated by 5.0 mm? (epr039-1.jpg = 8.85 ´ 10pr039-2.jpg Cpr039-3.jpg/N·mpr039-4.jpg)
 

 40. 
A 0.47 mF capacitor holds 1.0 mC of charge on each plate. What is the potential difference across the capacitor?
 

 41. 
What is the resistance of a resistor if the potential difference across the resistor is 4.0 V when a current of 10.0 A flows through the resistor?
 



 
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