| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.17 |
| Score | 0% | 63% |
You would measure the amount of resistance at a certain point in a circuit with a(n):
ammeter |
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voltmeter |
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ohmmeter |
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potentiometer |
Resistance is opposition to the flow of current and is measured in ohms (Ω). An ohmmeter is used to measure the amount of resistance at a certain point in a circuit.
Which of the following will increase the magnetic field produced by the electric current in a wire?
wind the wire into a coil |
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wrap the wire around a ceramic core |
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construct the wire from conductive material |
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construct the wire from insulative material |
A moving electric current produces a magnetic field proportional to the amount of current flow. This magnetic field can be made stronger by winding the wire into a coil and further enhanced if done around an iron containing (ferrous) core.
The diameter of a number 12 wire is __________ the diameter of a number 6 wire?
triple |
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double |
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less than |
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more than |
The larger the number the smaller the diameter of the wire. So, the diameter of a number 12 wire is less than the diameter of a number 6 wire.
In metals, increasing the temperature typically _____________ conductivity.
decreases |
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eliminates |
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does nothing to |
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increases |
All conductors have resistance and the amount of resistance varies with the element. Metals exhibit increased resistance (and, therefore, lower conductivity) as their temperature increases.
This circuit component symbol represents a(n):
capacitor |
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resistor |
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potentiometer |
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inductor |
Resistors are used to limit voltage and/or current in a circuit and can have a fixed or variable resistance. Variable resistors (often called potentiometers or rheostats) are used when dynamic control over the voltage/current in a circuit is needed, for example, in a light dimmer or volume control.