Chapter 13 Practice Name
________________________________________
Answer the following using
complete sentences.
1. An electric charge is present
in atoms. Where does it come from?
2. What is the difference between
conduction and induction?
4. Electric charges can move more
easily through some materials than others. What is the difference between a
good conductor and a good insulator? Give an example of each.
5. A static charge is caused by
electrons at rest. What is an electric current?
6. What is a circuit? What is the
function of a switch in a circuit?
7. What is the relationship
between the voltage in a circuit and the electric current?
8. How does resistance affect electric current? What kinds of wire provide low
resistance?
Calculate
Use Ohm’s Law to calculate the
missing measurements 1 to 5. Show your work to the right of the table.
Resistance
(R) |
Current
(I) |
Potential
Difference (V) |
1. |
6
amps |
12
V |
2. |
15
amps |
120
V |
50
ohms |
2
amps |
4. |
50
ohms |
1.5
amps |
5. |
3. |
2
amps |
150
V |
10. Read each statement about
series and parallel circuits. Write the term series or parallel next to the
proper statement.
a. All the lamps in
the circuit go out when one is removed. _________________
b. Each lamp is lit
as bright as it can be. _________________
c. Adding a lamp
decreases the brightness of the other lamps in the circuit. _________________
d. The amount of
current is the same in all parts of the circuit. _________________
11. a. Describe the current path
in a series circuit.
b. How is the current path in a
series circuit different from the path in a parallel circuit?
12. What is electric power? How
do you calculate power?
13. What is the function of a
ground wire on a plug?
14. Calculate the power and the
energy used by the following:
a. a 10-volt lamp that burns for 2 hours and has a current of 0.5 amp
b. a 60-watt light bulb that burns for 8 hours a day for 30 days
c. an oven that operates at 120 V and 10 amps for 3 hours
Check Your Knowledge
Choose the answer that best
completes each sentence.
15. A positive charge will repel
a (positive charge, negative charge).
16. An instrument that is used to
detect charges is a(n) (voltmeter, ammeter,
electroscope).
17. An example of a good
conductor is (copper, glass, wood).
18. Lightning occurs as a result
of a discharge of (resistance, static charges, amperes).
19. The closed, continuous path
through which electrons can flow is a(n) (circuit,
resistor, charge).
Determine whether each statement
is true or false. Write true if it is true. If it is false, change the
underlined word(s) to make the statement true.
_________________ 20. Ohm's law states that current in
a circuit is equal to voltage divided by charge.
_________________ 21. The Greek letter omega, W, is the symbol for the unit of resistance.
_________________ 22. A wet cell uses a(n) acid as its electrolyte.
_________________ 23. Fuses and circuit breakers
protect a circuit from short‑circuiting.
_________________ 24. A material that resists the flow
of electrons well is an insulator.
_________________ 25. The strongest part of an
electric field is the area farthest from the charge.
_________________ 26. A thermocouple uses differences
in temperature to generate electricity.
Apply the concepts you have
learned to answer each question.
27. If you know the charge of one
object, how could you use it to determine the charge of a second object?
28. Describe how lightning forms.