| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.20 |
| Score | 0% | 64% |
Why does current in an electric circuit create heat?
the wire in the circuit burns when current passes through |
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voltage is naturally hot |
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current is naturally hot |
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heat is created when the current overcomes resistance in the wire |
Current in an electric circuit creates heat when the current overcomes resistance in the wire.
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 circuit breaker can be reused |
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all of these |
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a fuse is cheaper than a circuit breaker |
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.
Capacitors connected in series produce __________ capacitance compared to capacitors connected in parallel.
less |
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more |
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no |
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the same |
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 connected in series produce less capacitance than capacitors connected in parallel.
In metals, increasing the temperature typically _____________ conductivity.
increases |
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decreases |
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does nothing to |
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eliminates |
All conductors have resistance and the amount of resistance varies with the element. Metals exhibit increased resistance (and, therefore, lower conductivity) as their temperature increases.
Which of the following allows current to pass easily in one direction and blocks current in the other direction?
diode |
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inductor |
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capacitor |
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resistor |
A diode allows current to pass easily in one direction and blocks current in the other direction. Diodes are commonly used for rectification which is the conversion of alternating current (AC) into direct current (DC). Because a diode only allows current flow in one direction, it will pass either the upper or lower half of AC waves (half-wave rectification) creating pulsating DC. Multiple diodes can be connected together to utilize both halves of the AC signal in full-wave rectification.