| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.28 |
| Score | 0% | 66% |
The conductivity of an element depends on how many electrons occupy which electron shell?
middle |
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inner |
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first |
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outer |
All electricity is the movement of electrons which are subatomic particles that orbit the nucleus of an atom. Electrons occupy various energy levels called shells and how well an element enables the flow of electrons depends on how many electrons occupy its outer (valence) electron shell.
This circuit component symbol represents a(n):
DC source |
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transistor |
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AC source |
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transformer |
In contrast to the constant one-way flow of direct current, alternating current changes direction many times each second. Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances.
A __________ electric current produces a magnetic field proportional to the amount of current flow.
stationary |
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low voltage |
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high voltage |
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moving |
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.
In household electrical wiring, which color of insulation indicates the 'hot' wire?
green |
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red |
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black |
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white |
In the NM cable used for wiring homes, each cable has three wires inside a sheath with each wire covered in a different color of insulation to indicate its type. The wire with the black insulation is the 'hot' wire, white is the neutral wire, and the ground wire is either covered in green insulation or left bare.
Alternating current changes __________ many times each second.
direction |
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period |
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frequency |
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resistance |
In contrast to the constant one-way flow of direct current, alternating current changes direction many times each second. Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances.