| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.69 |
| Score | 0% | 74% |
Electrical power is measured in:
amperes |
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watts |
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coulombs |
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volts |
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 electrical resistance is true?
the less resistive the conductor is the slower electron flow will be |
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the more resistive the conductor is the faster electron flow will be |
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electrically conductive materials have no resistive properties |
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the more resistive the conductor is the slower electron flow will be |
Resistance is opposition to the flow of current. As resistance increases, current decreases as resistance and current are inversely proportional.
Which of the following is the formula for calculating electrical power?
P = I2V |
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P = IV |
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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.
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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to discharge a capacitor safely, use a high-wattage resistor comparable to the capacitance of the capacitor |
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it is safe to touch a capacitor with your hands as long as it is small |
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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.
Using a fuse with a current rating higher than that required by a circuit:
makes no difference |
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is required |
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is recommended |
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makes the circuit less safe |
A fuse is a type of low resistance resistor that stops current flow in a circuit in response to a larger than intended electric current flow. Using a fuse with a higher current rating than required by a circuit is less safe as it could potentially allow overcurrent and risk a fire or heat-related equipment damage.