| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.34 |
| Score | 0% | 67% |
Which of these materials is not a good conductor of electricity?
tin |
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air |
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copper |
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gold |
All conductors have resistance and the amount of resistance varies with the element. In general, metals make the best conductors of electricity and non-metals make the worst conductors of electricity.
You would measure the amount of resistance at a certain point in a circuit with a(n):
voltmeter |
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potentiometer |
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ammeter |
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ohmmeter |
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.
This circuit component symbol represents a(n):
fuse |
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potentiometer |
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transformer |
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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.
In an electronic circuit, a thermocouple can be used to:
open or close a circuit at a designated temperature |
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increase or decrease the temperature of a component in the circuit |
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keep the circuit at a designated safe temperature |
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link the temperature of one component in the circuit to that of another component in the circuit |
A thermocouple is a temperature sensor that consists of two wires made from different conductors. The junction of these two wires produces a voltage based on the temperature difference between them and can be used like a switch to open or close the circuit at a designated temperature.
The formula specifying Ohm's law is which of the following?
\(V = {I \over R}\) |
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V = I2R |
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\(V = {R \over I}\) |
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V = IR |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.