| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.62 |
| Score | 0% | 72% |
Why is an insulator a poor conductor of electricity?
an insulator is made of inorganic material |
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an insulator has many free electrons |
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an insulator is made of organic material |
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an insulator has few free electrons |
Insulators have valence shells that are more than half full of electrons and, as such, are tightly bound to the nucleus and difficult to move from one atom to another.
Electrons will flow as current from areas of __________ potential (concentration of electrons) to areas of __________ potential.
high, low |
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low, low |
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low, high |
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high, high |
Voltage (V) is the electrical potential difference between two points. Electrons will flow as current from areas of high potential (concentration of electrons) to areas of low potential. Voltage and current are directly proportional in that the higher the voltage applied to a conductor the higher the current that will result.
This circuit component symbol represents a(n):
resistor |
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diode |
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fuse |
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capacitor |
Fuses are thin wires that melt when the current in a circuit exceeds a preset amount. They help prevent short circuits from damaging circuit components when an unusually large current is applied to the circuit, either through component failure or spikes in applied voltage.
The formula specifying Ohm's law is which of the following?
\(V = {R \over I}\) |
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V = IR |
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V = I2R |
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\(V = {I \over R}\) |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
Which of the following is the formula for calculating electrical power?
\(P = {I \over V}\) |
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P = I2V |
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\(P = {V \over I}\) |
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P = IV |
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.