| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.27 |
| Score | 0% | 65% |
Which of the following is not an advantage of semiconductors over conductors?
a semiconductor's conductivity can be varied under an external electrical field |
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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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materials to produce semiconductors are cheap and abundant |
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.
Which of the following statements about electrical resistance is true?
the less resistive the conductor is the slower electron flow will be |
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the more resistive the conductor is the slower electron flow will be |
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the more resistive the conductor is the faster electron flow will be |
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electrically conductive materials have no resistive properties |
Resistance is opposition to the flow of current. As resistance increases, current decreases as resistance and current are inversely proportional.
The voltage output of a transformer primarily depends on which of the following?
the diameter of the wire in the coils |
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the diameter of the coils |
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the number of turns in the wire of the coils |
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the conductor used for the wire in the coils |
A transformer utilizes an inductor to increase or decrease the voltage in a circuit. AC flowing in a coil wrapped around an iron core magnetizes the core causing it to produce a magnetic field. This magnetic field generates a voltage in a nearby coil of wire and, depending on the number of turns in the wire of the primary (source) and secondary coils and their proximity, voltage is induced in the secondary coil.
You would measure the amount of voltage between two points in a circuit with a(n):
ammeter |
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reostat |
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battery |
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voltmeter |
Voltage (V) is the electrical potential difference between two points. A voltmeter is used to measure the voltage between two points in a circuit.
Direct current flows from the __________ terminal of the voltage source to the __________ terminal.
positive, negative |
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positive, positive |
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negative, positive |
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negative, negative |
Direct current flows in only one direction in a circuit, from the negative terminal of the voltage source to the positive. A common source of direct current (DC) is a battery.