| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.98 |
| Score | 0% | 60% |
Which of the following is not true about a line drop?
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 |
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it is caused by resistance |
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it is addressed by raising current and lowering voltage across the ransmission 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.
Which of the following is not an advantage of semiconductors over conductors?
a semiconductor exhibits increased conductivity with increased temperatures |
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a semiconductor's conductivity can be varied under an external electrical field |
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materials to produce semiconductors are cheap and abundant |
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a semiconductor conducts current better than a conductor |
A semiconductor is a material that has a limited ability to conduct electrical current with conductivity between that of an insulator and that of a conductor. Silicon, a cheap and abundant material, is the most used semiconductor material although other materials are used in the electronics components made from semiconductors. The primary advantages of a semiconductor over a conductor is that the conductivity of a semiconductor can be varied under an external electrical field giving engineers precise control over complex circuits and, unlike conductors like metals, a semiconductor's conductivity increases with increased temperatures.
From what energy do photovoltaic cells produce electrical energy?
nuclear |
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magnetic |
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chemical |
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sun |
A photovoltaic cell (also known as a solar cell) converts energy from the sun into electrical energy.
This circuit component symbol represents a(n):
resistor |
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capacitor |
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transformer |
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inductor |
An inductor is coiled wire that stores electric energy in the form of magnetic energy and resists changes in the electric current flowing through it. If current is increasing, the inductor produces a voltage that slows the increase and, if current is decreasing, the magnetic energy in the coil opposes the decrease to keep the current flowing longer. In contrast to capacitors, inductors allow DC to pass easily but resist the flow of AC.
Why does current in an electric circuit create heat?
voltage is naturally hot |
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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 |
Current in an electric circuit creates heat when the current overcomes resistance in the wire.