| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.60 |
| Score | 0% | 72% |
You would measure the amount of voltage between two points in a circuit with a(n):
battery |
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ammeter |
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voltmeter |
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reostat |
Voltage (V) is the electrical potential difference between two points. A voltmeter is used to measure the voltage between two points in a circuit.
Why does current in an electric circuit create heat?
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 |
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the wire in the circuit burns when current passes through |
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 fuse is cheaper than a circuit breaker |
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a circuit breaker can be reused |
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all of these |
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 not true about a line drop?
it is addressed by raising current and lowering voltage across the ransmission line |
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it is a decrease in voltage between two points on a line |
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it is caused by resistance |
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it is addressed by raising voltage and lowering current across the transmission line |
Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances. A line drop is a decrease in voltage between two points on an electrical transmission line due to resistance in the line. A lower current and higher voltage across the line will help compensate for the line drop.
Which of the following statements about a capacitor is false?
you should always discharge any capacitors before working on an electronic circuit |
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to discharge a capacitor safely, use a high-wattage resistor comparable to the capacitance of the capacitor |
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it is safe to touch a capacitor with your hands as long as it is small |
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a capacitor remains charged even after the input voltage is removed |
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.