| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.19 |
| Score | 0% | 64% |
Which of the following will increase the magnetic field produced by the electric current in a wire?
wind the wire into a coil |
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wrap the wire around a ceramic core |
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construct the wire from conductive material |
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construct the wire from insulative material |
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.
Which of the following is not an advantage of semiconductors over conductors?
materials to produce semiconductors are cheap and abundant |
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a semiconductor conducts current better than a conductor |
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a semiconductor exhibits increased conductivity with increased temperatures |
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a semiconductor's conductivity can be varied under an external electrical field |
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.
Longer the electrical wires mean _______________ voltage drop.
diminishing |
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complete |
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greater |
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lesser |
Electrical wires have a certain amount of resistance per foot. A longer wire means more resistance and a greater voltage drop.
Resistance and current are __________ proportional.
exponentially |
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not |
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inversely |
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directly |
Resistance is opposition to the flow of current and is measured in ohms (Ω). One ohm is defined as the amount of resistance that will allow one ampere of current to flow if one volt of voltage is applied. As resistance increases, current decreases as resistance and current are inversely proportional.
Which of the following converts electrical energy into another form of energy in an electrical circuit?
AC source |
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DC source |
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wiring |
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load |
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.