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Name: ________________________ Class: ___________________ Date: __________
ID: A
Phys Electric Study Guide
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. If an atom gains electrons, it becomes a
a. positively charged ion.
b. negatively charged ion.
c.
d.
neutral atom.
neutral ion.
____
2. The strength of an electric field depends on the
a. amount of charge that produced the field.
b. distance from the charge.
c. amount of charge on a test charge placed in the field.
d. both A and B
____
3. What do electric forces between charges depend on?
a. the quantity of charge involved
c. both a. and b.
b. how far apart the charges are.
d. none of the above
____
4. Walking across a carpet is an example of charge being transferred by
a. contact.
c. static electricity.
b. induction.
d. friction.
____
5. If a neutral metal comb is held near an object with a negative charge, the comb will become charged by
a. induction.
c. friction.
b. contact.
d. static discharge.
____
6. An electrical insulator has
a. electrons that freely move.
b. more protons than electrons.
c.
d.
negatively charged ions.
electrons tightly bound to its atoms.
7. Resistance is affected by a material’s
a. thickness.
b. length.
c.
d.
temperature.
all of the above
____
____
8. Which of the following would reduce the resistance of a metal wire?
a. increasing its thickness
c. increasing its length
b. increasing its temperature
d. all of the above
____
9. The current in a hair dryer measures 15.0 amps. The resistance of the hair dryer is 8 ohms. What is the
voltage?
a. 120 V
c. 7 V
b. 0.5 V
d. 1800 V
____ 10. Which of the following represents Ohm’s law?
a. I = V × R
c.
b. V = I × R
d.
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R=V×I
V=I÷R
Name: ________________________
ID: A
____ 11. How many paths through which charge can flow would be shown in a circuit diagram of a series circuit?
a. one
c. none
b. two or more
d. more information is needed
____ 12. Most of the circuits in your home are
a. series circuits.
b. parallel circuits.
c.
d.
reversible circuits.
closed circuits.
____ 13. What is the unit of electric power?
a. ampere
b. volt
c.
d.
watt
ohm
Completion
Complete each statement.
14. The electric field around a positive charge points ____________________ the charge.
15. Electric force is ____________________ proportional to the amount of charge and ____________________
proportional to the square of the distance between the charges.
16. Like charges ____________________ and opposite charges ____________________.
17. When a pathway through which charges can move forms suddenly, ____________________ occurs.
18. The SI unit of electric current is the ____________________.
19. Scientists usually define the direction of current as the direction in which ____________________ charges
would flow.
20. Wood, plastic, and rubber are good electrical ____________________, and copper is a good electrical
____________________.
21. The SI unit of resistance is the ____________________.
22. A complete path through which charge can flow is an electric ____________________.
23. To calculate power, multiply voltage measured in ____________________ by ____________________
measured in amps.
24. The transfer of excess charge through a conductor to Earth is called ____________________.
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Name: ________________________
ID: A
Short Answer
Figure 20-1
25. In Figure 20-1, where is the field of each charge the strongest?
26. What is a charge’s electric field?
27. What are three ways that a charge can be transferred?
28. What is the law of conservation of charge?
29. What is the difference between direct current and alternating current?
30. Explain why metal wire coated with plastic or rubber is used in electric circuits.
31. What is the voltage in a circuit if the current is 4 amps and the resistance is 4 ohms? Explain your answer.
32. If the voltage in a circuit is 80 volts and the resistance is 20 ohms, what is the current? Explain your answer.
33. How much energy does a 50-watt light bulb use compared to a 100-watt light bulb if both are shining for the
same length of time? Explain your answer.
34. What is a circuit breaker?
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