| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.59 |
| Score | 0% | 72% |
Why is an insulator a poor conductor of electricity?
an insulator is made of organic material |
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an insulator has few free electrons |
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an insulator has many free electrons |
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an insulator is made of inorganic material |
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.
What is the potential difference in an electrical circuit a measure of?
the current at a specific location in the circuit |
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the voltage at a specific location in the circuit |
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the load at a specific location in the circuit |
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the resistance at a specific location in the circuit |
Electrons flow from an area of high concentration to an area of low concentration. A high voltage indicates a high concentration of electrons that creates a greater potential for electron flow than a low voltage. When applied to a load, voltage creates electricity and potential difference is the measure of voltage at a specific location in an electrical circuit.
| 1 A | |
| 2 A | |
| 6 A | |
| 3.5 A |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
Solved for current, I = \( \frac{V}{R} \) = \( \frac{100}{50} \) = 2 A
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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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 |
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you should always discharge any capacitors before working on an electronic circuit |
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.
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.