| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.47 |
| Score | 0% | 69% |
In an electrical circuit, resistors have fixed or __________ resistance.
parallel |
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dynamic |
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variable |
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series |
Resistors are used to limit voltage and/or current in a circuit and can have a fixed or variable resistance. Variable resistors (often called potentiometers or rheostats) are used when dynamic control over the voltage/current in a circuit is needed, for example, in a light dimmer or volume control.
Longer the electrical wires mean _______________ voltage drop.
diminishing |
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complete |
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lesser |
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greater |
Electrical wires have a certain amount of resistance per foot. A longer wire means more resistance and a greater voltage drop.
A capacitor is often used for which of the following purposes?
to convert alternating current into direct current |
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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 |
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.
The joule is a unit of measurement for:
capacitance |
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energy |
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resistance |
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power |
The joule is a unit of measurement for energy.
Current is the rate of flow of electrons per unit time and is measured in:
volts |
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coulombs |
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amperes |
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ohms |
Current is the rate of flow of electrons per unit time and is measured in amperes (A). A coulomb (C) is the quantity of electricity conveyed in one second by a current of one ampere.