| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.48 |
| Score | 0% | 70% |
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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the more resistive the conductor is the faster electron flow will be |
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electrically conductive materials have no resistive properties |
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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.
The volt is a unit of measurement for:
capacitance |
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current |
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power |
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voltage |
Voltage (V) is the electrical potential difference between two points. Electrons will flow as current from areas of high potential (concentration of electrons) to areas of low potential. Voltage and current are directly proportional in that the higher the voltage applied to a conductor the higher the current that will result.
Inductance is a factor in which of the following?
a DC circuit |
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determining energy stored by a capacitor |
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an AC circuit |
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batteries connected in serial |
Inductance is a property of an AC circuit (or a component in an AC circuit) that quantifies resistance to changes in current. The current in an AC circuit is continuously changing and inductive reactance (the opposition to change) depends both on the inductance of the circuit or component and the rate at which the current is changing.
A capacitor is often used for which of the following purposes?
as a primary power source |
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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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to convert alternating current into direct current |
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.
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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silver and gold are brittle |
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all of these |
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copper is durable and relatively cheap |
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.