| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.51 |
| Score | 0% | 70% |
Which of the following is not true about a line drop?
it is addressed by raising current and lowering voltage across the ransmission line |
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it is caused by resistance |
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it is a decrease in voltage between two points on a line |
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it is addressed by raising voltage and lowering current across the transmission line |
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.
Silver and gold are among the most highly conductive elements. Why is copper used much more often as a conductor in electrical circuits?
silver and gold are costly |
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copper is durable and relatively cheap |
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all of these |
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silver and gold are brittle |
All conductors have resistance and the amount of resistance varies with the element. But, resistance isn't the only consideration when choosing a conductor as the most highly conductive elements like silver and gold are also more expensive and more brittle than slightly less conductive elements like copper. A balance needs to be struck between the electrical qualities of a material and its cost and durability.
Which of the following statements about electrical resistance is true?
the more resistive the conductor is the slower electron flow will be |
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electrically conductive materials have no resistive properties |
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the more resistive the conductor is the faster electron flow will be |
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the less resistive the conductor is the slower electron flow will be |
Resistance is opposition to the flow of current. As resistance increases, current decreases as resistance and current are inversely proportional.
Why does current in an electric circuit create heat?
current is naturally hot |
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the wire in the circuit burns when current passes through |
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heat is created when the current overcomes resistance in the wire |
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voltage is naturally hot |
Current in an electric circuit creates heat when the current overcomes resistance in the wire.
Electrical power is measured in:
amperes |
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coulombs |
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watts |
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volts |
Electrical power is measured in watts (W) and is calculated by multiplying the voltage (V) applied to a circuit by the resulting current (I) that flows in the circuit: P = IV. In addition to measuring production capacity, power also measures the rate of energy consumption and many loads are rated for their consumption capacity. For example, a 60W lightbulb utilizes 60W of energy to produce the equivalent of 60W of heat and light energy.