| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.44 |
| Score | 0% | 69% |
What is the potential difference in an electrical circuit a measure of?
the resistance 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 current at a specific location in the circuit |
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the load 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.
In an electrical circuit, resistors have fixed or __________ resistance.
variable |
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series |
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dynamic |
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parallel |
Resistors are used to limit voltage and/or current in a circuit and can have a fixed or variable resistance. Variable resistors (often called potentiometers or rheostats) are used when dynamic control over the voltage/current in a circuit is needed, for example, in a light dimmer or volume control.
The valence shell of a semiconductor is how full of electrons?
more than half full |
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half full |
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empty |
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less than half full |
Semiconductors have valence shells that are exacly half full and can conduct electricity under some conditions but not others. This property makes them useful for the control of electrical current.
Which of the following statements about a capacitor is false?
a capacitor remains charged even after the input voltage is removed |
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you should always discharge any capacitors before working on an electronic circuit |
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it is safe to touch a capacitor with your hands as long as it is small |
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to discharge a capacitor safely, use a high-wattage resistor comparable to the capacitance of the capacitor |
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.
Which of the following statements about electrical resistance is true?
the more resistive the conductor is the faster electron flow will be |
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the less resistive the conductor is the slower electron flow will be |
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the more resistive the conductor is the slower electron flow will be |
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electrically conductive materials have no resistive properties |
Resistance is opposition to the flow of current. As resistance increases, current decreases as resistance and current are inversely proportional.