| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.37 |
| Score | 0% | 67% |
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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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 |
Current in an electric circuit creates heat when the current overcomes resistance in the wire.
From what energy do photovoltaic cells produce electrical energy?
nuclear |
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magnetic |
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chemical |
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sun |
A photovoltaic cell (also known as a solar cell) converts energy from the sun into electrical energy.
You would measure the amount of current through a circuit with a(n):
potentiometer |
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voltmeter |
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battery |
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ammeter |
Current is the rate of flow of electrons per unit time and is measured in amperes (A). An ammeter is used to measure the electric current in a circuit.
Which of the following is the formula for calculating electrical power?
P = IV |
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P = I2V |
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\(P = {I \over V}\) |
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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.
In household electrical wiring, which color of insulation indicates the 'hot' wire?
red |
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black |
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green |
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white |
In the NM cable used for wiring homes, each cable has three wires inside a sheath with each wire covered in a different color of insulation to indicate its type. The wire with the black insulation is the 'hot' wire, white is the neutral wire, and the ground wire is either covered in green insulation or left bare.