| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.55 |
| Score | 0% | 71% |
The watt is a unit of measurement for:
resistance |
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frequency |
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energy |
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power |
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.
Which of the following statements about a capacitor is false?
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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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 |
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.
A diode to an electronic circuit is like a _______________ to a city?
highway |
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traffic light |
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one-way street |
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parking lot |
A diode allows current to pass easily in one direction and blocks current in the other direction.
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 resistance 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 voltage 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.
The formula specifying Ohm's law is which of the following?
V = I2R |
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\(V = {I \over R}\) |
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\(V = {R \over I}\) |
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V = IR |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.