| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.01 |
| Score | 0% | 60% |
Alternating current changes __________ many times each second.
frequency |
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direction |
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resistance |
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period |
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.
The valence shell of a conductor is how full of electrons?
half full |
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less than half full |
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more than half full |
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full |
Conductors are elements that allow electrons to flow freely. Their valence shell is less than half full of electrons that are able to move easily from one atom to another.
A capacitor is often used for which of the following purposes?
to convert alternating current into direct current |
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to allow a small amount of current to control a large amount of current |
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to maintain power in a circuit when the primary power source is disconnected |
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as a primary power source |
Capacitors store electricity and are used in circuits as temporary batteries. Capacitors are charged by DC current (AC current passes through a capacitor) and that stored charge can later be dissipated into the circuit as needed. Capacitors are often used to maintain power within a system when it is disconnected from its primary power source or to smooth out or filter voltage within a circuit.
Which of the following is not true about a line drop?
it is addressed by raising voltage and lowering current across the transmission line |
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it is addressed by raising current and lowering voltage across the ransmission line |
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it is a decrease in voltage between two points on a line |
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it is caused by resistance |
Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances. A line drop is a decrease in voltage between two points on an electrical transmission line due to resistance in the line. A lower current and higher voltage across the line will help compensate for the line drop.
A capacitor to an electronic circuit is like a _______________ to a house?
storage shed |
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gate |
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safe |
|
driveway |
Capacitors store electricity and are used in circuits as temporary batteries. Capacitors are charged by DC current (AC current passes through a capacitor) and that stored charge can later be dissipated into the circuit as needed. Capacitors are often used to maintain power within a system when it is disconnected from its primary power source or to smooth out or filter voltage within a circuit.