Extended Response
19.1 Ohm's law
61
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Explain how current and charge are related, including how direction is defined.
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Current is the ratio of charge passing through a conductor per unit time. The current’s direction is the direction in which protons would flow.
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Charge is the ratio of current passing through a conductor per unit time. The charge’s direction is the direction in which protons would flow.
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Current is the product of charge passing through a conductor and the amount of time that passes. The current’s direction is the direction in which electrons would flow.
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Charge is the product of current passing through a conductor and time. The charge’s direction is the direction in which electrons would flow.
62
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Under what conditions might a resistor material that normally follows Ohm’s law become non-ohmic?
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If the amount of current flowing through the material is too low, the resistor may heat up, creating a nonlinear relationship between current and voltage.
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If the amount of current flowing though the material is too high, the resistor may heat up, creating a nonlinear relationship between current and voltage.
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If the amount of current flowing through the material is too low, the resistor may not warm up enough to allow a nonlinear relationship between current and voltage.
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If the amount of current flowing through the material is too high, the resistor may not warm up enough to allow a nonlinear relationship between current and voltage.
63
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You connect a single resistor across a battery and find that flows through the circuit. You add another resistor after the first resistor and find that flows through the circuit. If you have resistors connected in a line one after the other, what would be their total resistance?
19.2 Series Circuits
64
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Explain why the current is the same at all points in the circuit below.
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If the current were not constant, the mobile charges would bunch up in places, which means that the voltage would decrease at that point. A lower voltage at some point would push the current in the direction that further decreases the voltage.
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If the current were not constant, the mobile charges would bunch up in places, which means that the voltage would increase at that point. But a higher voltage at some point would push the current in the direction that decreases the voltage.
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If the current were not constant, the mobile charges would bunch up in places, which mean that the voltage would increase at that point. A higher voltage at some point would push the current in the direction that further increases the voltage.
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If the current were not constant, the mobile charges would bunch up in places, which mean that the voltage would decrease at that point. But a lower voltage at some point would push the current in the direction that increases the voltage.
65.
What is the current through each resistor in the circuit?
- Current through resistors R1, R2, R3, and R4 is 0.48 A, 0.30 A, 1.2 A, and 0.24 A, respectively.
- Current through resistors R1, R2, R3, and R4 is 1200 A, 1920 A, 480 A, and 2400 A, respectively.
- Current through resistors R1, R2, R3, and is R4 2.08 A, 3.34 A, 0.833 A, and 4.17 A, respectively.
- The same amount of current, 0.096 A, flows through all of the resistors.
19.3 Parallel Circuits
66
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Power is supplied to a circuit in a house by one incoming wire at high potential compared with the ground. How does the voltage at each outlet on the circuit change and why?
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All outlets on the circuit have the same voltage because they are wired in parallel.
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All outlets on the circuit have the same voltage because they are wired in series.
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Outlets further away from the source have a lower voltage because they are wired in parallel.
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Outlets further away from the source have a lower voltage because they are wired in series.
19.4 Electric Power
67
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A single resistor is connected across the terminals of a battery When you attach a second resistor in parallel with the first, does the power dissipated by the system change?
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No, the power dissipated remain same.
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Yes, the power dissipated increases.
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Yes, the power dissipated decreases.
68
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In a flashlight, the batteries are normally connected in series. Why are they not connected in parallel?
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Batteries are connected in series for higher voltage and power output.
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Batteries are connected in series for lower voltage and power output.
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Batteries are connected in series so that power output is a much lower for the same amount of voltage.
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Batteries are connected in series to reduce the overall loss of energy from the circuit.