- Your instructor makes the following statement:
“A short circuit is a wire or other conducting path that can have a large current when connected directly from the positive to the negative terminal of a battery. The current is large because the battery voltage is applied to a circuit with almost zero resistance.”
Which of the following best summarizes the instructor’s statement? - A wire or conducting path can have a large current.
- A battery has essentially zero resistance.
- A short circuit has essentially zero resistance and can result in large currents.
- A short circuit is a circuit that connects the positive and negative terminals of a battery.
 Do electric utility companies charge their customers using units of energy or power? Why not charge using the other quantity?
- Ned turned on his home stereo, computer, washer, electric dryer, and the lights in every room. The circuit breaker then tripped. Is there anything he should do before flipping the circuit breaker switch?
- How does a fuse differ from a circuit breaker?
- How are electric current, voltage, and power related to each other?
- When connecting a mini-lamp and socket to a circuit breadboard, why must you connect the leads to different rows of the circuit breadboard?
- Four resistors are connected in series. The individual resistances are 10 Ω, 20 Ω, 99 Ω, and 23 Ω. If the current through the first resistor is 0.1 A, what is the current through each of the other three resistors?
- Draw a circuit diagram with a battery, resistor, and lamp, where the lamp and resistor are connected in series.
- Draw a circuit diagram with a battery, resistor, and two lamps, where the lamps and resistor are connected in parallel.
 If two resistors are connected in series, is their effective resistance larger or smaller than either of their individual resistances? Why?
- Design a circuit with a battery and two resistors all connected in series.
| | - Design a circuit with two resistors connected in parallel with each other and both connected to a battery.
- A sales person in a store tells you that all light bulbs labeled 100 W will radiate 100 W of power when connected to a 120 V outlet. As evidence to support his claim, he plugs two different 100 W bulbs into a socket and points out that they are equally bright.
- In your analysis, did the scientific evidence support the sales person’s claim?
- If the sales person’s claim were true, what should happen if you connected two 100 W bulbs in series to the power outlet?
- Based on what you know about circuits, what will actually happen to the brightness of two 100 W bulbs connected in series with the power outlet? Would this support or contradict the sales person’s assertion?
- Based on what you know about circuits, propose an alternate hypothesis for how much power a 100 W bulb will radiate.
- If two resistors are connected in parallel, is their effective resistance larger or smaller than either of their individual resistances? Why?
- Do three lamps shine more brightly if they are connected in series or in parallel? Defend your answer.
- Lamps are rated in terms of maximum power output based on the amount of heat they can withstand. If you connect a bulb to a lamp that draws more power than the lamp’s rating, you can start a fire. Based on this information, are bulbs with higher resistive elements safer or more dangerous?
- Estrella had one resistor connected to a battery, resulting in a current of 0.01 A. She wanted more resistance in her circuit to reduce the total current. So she took two identical resistors and connected their ends as shown above. Will she succeed?
- Disassemble a flashlight that uses more than one battery, but without damaging its components or operation. Inspect the wires inside. How are the batteries connected together, in series or in parallel?
 There are two resistors in a simple circuit, R1 and R2. Resistor R1 has a voltage drop across it that is 1/3 the voltage drop across R2. Which element has more current flowing through it?
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