Download Name: 1. Comparisons Electrical resistance is sometimes explained

Name: 1. Comparisons Electrical resistance is sometimes explained by
saying that it is like friction for electric current. Describe how
resistance and friction are alike and how they may be
different.
2. Explain the energy changes involved when a positive charge
moves because of a nearby, negatively charged object. Use
the terms electrical potential energy, work, and kinetic
energy in your answer.
3. What causes resistance in an electric circuit? How is
resistance measured?
4. How do charges move through an insulated wire connected
across a battery? Use the terms potential difference, electric
current, electrical conductor, and electrical insulator in your
answer.
5. How would you ground an electrical appliance?
6. Contrast the movement of charges in a series circuit and in a
parallel circuit. Use a diagram to aid in your explanation.
7. If a string of lights goes out when one of the bulbs is
removed, are the lights probably connected in a series circuit
or a parallel circuit? Explain your answer.
8. Explain the difference between a fuse and a circuit breaker. If
you were designing a circuit for a reading lamp, would you
include a fuse, a circuit breaker, or neither? Explain your
answer.
9. If two charges attract each other,
A. both charges must be positive.
B. both charges must be negative.
C. the charges must be different.
D. the charges must be the same.
10. The electric force between two objects depends on all of the following except
A. the distance between the objects.
B. the electric charge of the first object.
C. the way that the two objects became electrically charged.
D. the electric charge of the second object.
11. In the figure below,
A. the positive charge is greater than the negative charge.
B. the negative charge is greater than the positive charge.
C. both charges are positive.
D. both charges are negative.
12. In order to produce a current in a cell, the terminals must
A. have a potential difference.
B. be exposed to light.
C. be in a liquid.
D. be at two different temperatures.
13. An electric current does not exist in
A. a closed circuit.
B. a series circuit.
C. a parallel circuit.
D. an open circuit.
14. Which of the following can help prevent a circuit from overloading?
A. a resistor
B. a switch
C. a galvanometer
D. a fuse
15. Which of the diagrams represent circuits that cannot have
current in them as drawn?
16. Describe the characteristics of the electric field due to a
single positive charge. How does the electric field of a
negative charge differ?
17. Compare and contrast conductors, superconductors,
semiconductors, and insulators.
18. Explain how fuses and circuit breakers are used to prevent
circuit overload.
19. Making Comparisons The gravitational force is always
attractive, and the electric force is both attractive and
repulsive. What accounts for this difference?
20. Understanding Relationships Why is charge usually
transferred by electrons? Which materials transfer electrons
most easily? In what situations can positive charge move?
21. Designing Systems How many ways can you connect three
light bulbs and a battery in a circuit? Draw a schematic
diagram of each circuit.
22. Applying Knowledge At a given voltage, which light bulb
has the greater resistance, a 200 W light bulb or a 75 W light
bulb? Explain.
23. The graph below shows how electrical potential energy
changes as the distance between two charges changes. Is the
second charge positive or negative? Explain.
24. Electric Force Electric force is directly proportional to the
product of the charges and inversely proportional to the
square of the distance between them. If q1 and q2 are the
charges on two objects and d is the distance between them,
which of the following represents the electric force, F,
between them?
25. Resistance A potential difference of 12 V produces a current
of 0.30 A in a piece of copper wire. What is the resistance of
the wire?
26. Resistance What is the voltage across a 75 Ω resistor with
1.6 A of current?
27. Electric ower A portable cassette player uses 3.0 V (two 1.5
V batteries in series) and has 0.33 A of current. What is its
power rating?
28. Electric ower Find the current in a 2.4 W flashlight bulb
powered by a 1.5 V battery.