| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.34 |
| Score | 0% | 67% |
Electrical power is measured in:
amperes |
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watts |
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coulombs |
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volts |
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 convert alternating current into direct 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 allow a small amount of current to control a large amount of 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.
Which of the following allows DC to pass easily but resists the flow of AC?
transformer |
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inductor |
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semiconductor |
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capacitor |
An inductor is coiled wire that stores electric energy in the form of magnetic energy and resists changes in the electric current flowing through it. If current is increasing, the inductor produces a voltage that slows the increase and, if current is decreasing, the magnetic energy in the coil opposes the decrease to keep the current flowing longer. In contrast to capacitors, inductors allow DC to pass easily but resist the flow of AC.
Which of the following is a characteristic of batteries connected in series?
total voltage equals the sum of the individual battery voltages |
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the positive terminal of one battery is connected to the positive terminal of the next |
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total voltage equals the average of the individual battery voltages |
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two connections are made between each adjacent battery |
You can multiply the voltage or the current supplied by individual batteries by connecting them together either in series or in parallel. The characteristics of batteries connected in series are that total voltage equals the sum of the individual battery voltages, total current equals the average of the individual battery currents, the positive terminal of one battery is connected to the negative terminal of the next, and one connection is made between each adjacent battery.
Electrons will flow as current from areas of __________ potential (concentration of electrons) to areas of __________ potential.
high, high |
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low, low |
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low, high |
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high, low |
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.