| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.73 |
| Score | 0% | 75% |
The formula specifying Ohm's law is which of the following?
V = IR |
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\(V = {R \over I}\) |
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V = I2R |
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\(V = {I \over R}\) |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
Electrons will flow as current from areas of __________ potential (concentration of electrons) to areas of __________ potential.
high, high |
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low, high |
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low, low |
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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.
Which of the following is a difference between a circuit breaker and a fuse?
a fuse responds more quickly than a circuit breaker |
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a fuse is cheaper than a circuit breaker |
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all of these |
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a circuit breaker can be reused |
Like fuses, circuit breakers stop current flow once it reaches a certain amount. They have the advantage of being reusable (fuses must be replaced when "blown") but respond more slowly to current surges and are more expensive than fuses.
Which of the following is the formula for calculating electrical power?
\(P = {I \over V}\) |
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P = I2V |
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P = IV |
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\(P = {V \over I}\) |
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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to convert alternating current into direct current |
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to maintain power in a circuit when the primary power source is disconnected |
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as a primary power source |
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.