| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.27 |
| Score | 0% | 65% |
Why does current in an electric circuit create heat?
the wire in the circuit burns when current passes through |
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heat is created when the current overcomes resistance in the wire |
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current is naturally hot |
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voltage is naturally hot |
Current in an electric circuit creates heat when the current overcomes resistance in the wire.
Which of the following is not a characteristic of direct current?
used to power your cell phone |
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an example power source is a generator |
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cannot easily travel distances without power loss |
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electrons flow in only one consistent direction |
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 DC is a battery. In contrast to the constant one-way flow of direct current, alternating current changes direction many times each second. Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances.
The joule is a unit of measurement for:
resistance |
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power |
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capacitance |
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energy |
The joule is a unit of measurement for energy.
What is the primary difference between a rectifier and an inverter?
a rectifier strips out the DC portion of electricity while an inverter strips out the AC portion |
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a rectifier converts a DC input to AC while an inverter converts an AC input to DC |
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a rectifier strips out the AC portion of electricity while an inverter strips out the DC portion |
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a rectifier converts an AC input to DC while an inverter converts a DC input to AC |
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.
One of the lights on your Christmas tree burns out and this causes the rest of the lights connected to that strand to go dark. How are the lights in that strand connected?
series-parallel |
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parallel |
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series |
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perpendicular |
Lights connected in series form a chain with each light connecting to adjacent lights via one wire. Therefore, if one of the lights burns out and breaks the series, none of the other lights will receive power and they'll go dark. Lights connected in parallel each connect to the positive and negative nodes of the power source and would not go dark if one of their neighbors burnt out.