| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.53 |
| Score | 0% | 71% |
Resistance is opposition to which of the following?
conductance |
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voltage |
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impedance |
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current |
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.
This circuit component symbol represents a(n):
transistor |
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AC source |
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transformer |
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DC source |
In contrast to the constant one-way flow of direct current, alternating current changes direction many times each second. Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances.
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 less 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.
Electrical power is measured in:
volts |
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watts |
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coulombs |
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amperes |
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.
A capacitor is often used for which of the following purposes?
to allow a small amount of current to control a large amount of current |
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as a primary power source |
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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.