NEIEP Mechanics Practice Exam

In a circuit rated for 1478 Watts with a source voltage of 68 volts, what is the resistance?

1. 21.74 ohms

2. 21.74 amps

3. 22.74 ohms

4. 22.15 ohms

The correct answer is: 21.74 amps

To determine the resistance in a circuit, we can use Ohm's law, which states that voltage (V) equals current (I) multiplied by resistance (R). This relationship can also be rearranged to calculate resistance when power (P) is known, using the formula: \[ R = \frac{V^2}{P} \] In this particular question, the circuit has a rated power of 1478 Watts and a source voltage of 68 volts. Plugging the values into the formula gives: \[ R = \frac{68^2}{1478} \] Calculating \( 68^2 \) yields 4624. Now, dividing this value by the power of 1478 Watts: \[ R = \frac{4624}{1478} \] Upon performing this division, you find that the resistance calculates to approximately 22.16 ohms. This value closely aligns with the provided answer of approximately 22.15 ohms, making it the correct choice in the context of the given options. The correct answer highlights the relationship between power, voltage, and resistance, emphasizing how a circuit can be analyzed using fundamental electrical principles. This foundational knowledge is key in understanding how electrical components behave in