Download Circuits Study Guide Note: These questions are not meant to be 100

Circuits Study Guide
Note: These questions are not meant to be 100% representative of the test you will have. However, if you study
your notes, book, homework, and labs, and then are able to answer all of these questions, you are probably well
situated for the upcoming test.
1. Know the definitions and units for physical quantities used in electricity and magnetism.
2. Know the rules for series and parallel circuits (what’s the same, what’s different, and
conceptually why these rules exist). Also be able to solve series, parallel, and combination
circuits.
3. Know conceptually what our currently accepted model of magnetism is. Know the relationship
(conceptually) between magnetism and electricity per our class discussion and labs (Your book
goes into much more detail than we have). Review the magnetism labs and power point for big
ideas.
4. What are the necessary elements of any electric circuit and why is each necessary?
5. What is the role of a battery in electric circuit? How do you know what a battery does?
6. When you open the valve to a water faucet, water rushes out. Explain why electric charge does
not get pushed out the end of a wire attached to the terminal of a battery.
7. How can you measure electric current through a resistor? (b) How can you measure voltage
across a resistor?
8. What does it mean if the current through a resistor is 3 A? (b) What does it mean if the voltage
across the resistor is 3 V? (c) What does it mean if the resistance of the resistor is 3 Ω?
9. Why do resistors become warm and sometimes hot when electric current passes through them?
10. Explain how you can calculate the electric power that is generated in a conductor when there is
electric current through it.
11. Why do we connect resistive elements in a home in parallel rather than in series?
12. You have two light bulbs: one is a 40-W light bulb, the other a 100-W bulb. What do these
readings mean?
13. Most modern Christmas tree lights are connected in parallel. (a) Describe one advantage of
lights connected in parallel. (b) Suppose you connect these lights in series. Will they be brighter
or darker? Explain.
14. You have a switch and a 75-W and a 40-W bulb. Build a circuit satisfying the following condition:
when the switch is on, the 75-W light bulb is on. When the switch is off, the 75-W bulb no longer
glows, but the 40-W bulb does.
15. How does a light bulb work? What are the essential parts of a circuit? (i.e. what are the
minimum things you would need to have a circuit?)
16. Your friend has built a circuit and forgot if the resistors are connected in series or parallel.
Describe a method for how you can test if it is a series circuit or a parallel circuit.
17. A 20 Ω, 30 Ω, and 40 Ω set of resistors are in series to a 12-V battery. What is the potential
difference across the 40 Ω resistor?
18. A 20 Ω, 30 Ω, and 40 Ω set of resistors are in parallel to a 12-V battery. What is the current
through the 40 Ω resistor?
19. When you turn on too many appliances in your house, you can lose electric power in the whole
house. This happens because the wires connecting the house to the power line get overheated
and a safety device, called a circuit breaker, opens the circuit, preventing the current flow. Why
would the wires connecting the house to the power line overheat when you turn on many
appliances?
20. Find total current, current in all branches, and voltage drops across each resistor for the circuit
shown.
21. Your friend says that when two identical light bulbs
are connected in series to each other and then to a
battery, the light bulb connected closest to the
negative pole of the battery will be brighter. He
explains this by claiming that the second bulb will get
fewer electrons, because the first bulb will use up
some of the electrons. Do you agree or disagree?
22. Calculate total current, branch currents, and voltage drops across each resistor in the circuit
shown.
23. Given the diagram below, where R1 = 5Ω, R2 = 10Ω, R3 = 20Ω, find the total resistance between
points A and B .