| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.69 |
| Score | 0% | 74% |
| 5 A | |
| 4.5 A | |
| 3 A | |
| 1.5 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 = \( \frac{V}{R} \) = \( \frac{270}{90} \) = 3 A
What type of current flows in only one direction in a circuit?
alternating |
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direct |
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parallel |
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series |
Direct current flows in only one direction in a circuit, from the negative terminal of the voltage source to the positive. A common source of direct current (DC) is a battery.
| 48V 5A | |
| 24V 10A | |
| 12V 20A | |
| 96V 40A |
Connecting the 4 batteries in series multiplies their voltage while keeping their current the same yielding a 48V 5A configuration. Connecting the 4 batteries in parallel multiplies their current while keeping their voltage the same yielding a 12V 20A configuration. Using a series-parallel connection, 2 batteries can be connected in series and 2 can be connected in parallel resulting in a 24V 10A configuration.
Which of the following is a difference between a circuit breaker and a fuse?
a fuse responds more quickly than a circuit breaker |
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all of these |
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a circuit breaker can be reused |
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a fuse is cheaper than a circuit breaker |
Like fuses, circuit breakers stop current flow once it reaches a certain amount. They have the advantage of being reusable (fuses must be replaced when "blown") but respond more slowly to current surges and are more expensive than fuses.
The ohm is a unit of measurement for:
resistance |
|
power |
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capacitance |
|
energy |
Resistance is opposition to the flow of current and is measured in ohms (Ω). One ohm is defined as the amount of resistance that will allow one ampere of current to flow if one volt of voltage is applied. As resistance increases, current decreases as resistance and current are inversely proportional.