| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.09 |
| Score | 0% | 62% |
Which of the following is a difference between a circuit breaker and a fuse?
a circuit breaker can be reused |
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a fuse is cheaper than a circuit breaker |
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all of these |
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a fuse responds more quickly than a circuit breaker |
Like fuses, circuit breakers stop current flow once it reaches a certain amount. They have the advantage of being reusable (fuses must be replaced when "blown") but respond more slowly to current surges and are more expensive than fuses.
The valence shell of n insulator is how full of electrons?
empty |
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half full |
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more than half full |
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less 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.
Which of the following is not a characteristic of a step-up transformer?
the primary voltage is higher than the secondary voltage |
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the secondary voltage is higher than the primary voltage |
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increases voltage |
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has more turns in the secondary winding than in the primary winding |
As their names indicate, a step-up transformer is used to step up or increase voltage and a step-down transformer is used to step down or decrease voltage. In a step-up transformer, the secondary voltage is higher than the primary voltage and it has more turns in the secondary winding than in the primary winding.
What is the voltage of most household electrical systems in the United States?
110V |
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60Hz |
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220V |
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60V |
Most households use electricity with a voltage of 110V.
A __________ electric current produces a magnetic field proportional to the amount of current flow.
high voltage |
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moving |
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low voltage |
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stationary |
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.