| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.34 |
| Score | 0% | 67% |
Alternating current changes __________ many times each second.
period |
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direction |
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resistance |
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frequency |
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.
Why is an insulator a poor conductor of electricity?
an insulator has many free electrons |
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an insulator is made of inorganic material |
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an insulator has few free electrons |
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an insulator is made of organic material |
Insulators have valence shells that are more than half full of electrons and, as such, are tightly bound to the nucleus and difficult to move from one atom to another.
Which of the following converts electrical energy into another form of energy in an electrical circuit?
DC source |
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AC source |
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load |
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wiring |
A load is a source of resistance that converts electrical energy into another form of energy. The components of a microwave, for example, are loads that work together to convert household electricity into radation that can be used to quickly cook food.
The valence shell of n insulator is how full of electrons?
empty |
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half full |
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less than half full |
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more than half full |
Insulators have valence shells that are more than half full of electrons and, as such, are tightly bound to the nucleus and difficult to move from one atom to another.
Why does current in an electric circuit create heat?
the wire in the circuit burns when current passes through |
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current is naturally hot |
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voltage is naturally hot |
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heat is created when the current overcomes resistance in the wire |
Current in an electric circuit creates heat when the current overcomes resistance in the wire.