| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.75 |
| Score | 0% | 75% |
Direct current flows from the __________ terminal of the voltage source to the __________ terminal.
negative, positive |
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negative, negative |
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positive, positive |
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positive, negative |
Direct current flows in only one direction in a circuit, from the negative terminal of the voltage source to the positive. A common source of direct current (DC) is a battery.
Which of the following statements about a capacitor is false?
it is safe to touch a capacitor with your hands as long as it is small |
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you should always discharge any capacitors before working on an electronic circuit |
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a capacitor remains charged even after the input voltage is removed |
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to discharge a capacitor safely, use a high-wattage resistor comparable to the capacitance of the capacitor |
The purpose of a capacitor is to retain electric charge and it will do so even after its input voltage is removed. After the input voltage is removed, the capacitor will slowly discharge but, depending on the size and characteristics of the capacitor, discharging could take from a few minutes to a few years. So, it's never safe to touch a capacitor with your hands and you should make sure to discharge any capacitors in a circuit before working on it using an appropriately high-wattage resistor or a capacitor discharge tool.
Which of the following is a difference between a circuit breaker and a fuse?
all of these |
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a fuse is cheaper than a circuit breaker |
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a fuse responds more quickly than a circuit breaker |
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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 statements about electrical resistance is true?
electrically conductive materials have no resistive properties |
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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 slower electron flow will be |
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the more resistive the conductor is the faster electron flow will be |
Resistance is opposition to the flow of current. As resistance increases, current decreases as resistance and current are inversely proportional.
The ohm is a unit of measurement for:
energy |
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power |
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resistance |
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capacitance |
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.