FCC Exam Question: 6A207

Given a solenoid with a resistance of 5 ohms and 0.34 through the winding when 1108 at 60 Hz isapplied. What is the impedance?

A. 367 ohms
B. 350 ohms
C. 360 ohms
D. None of the above
Correct Answer: A

Explanation: The impedance (Z) of an AC circuit is the total opposition to current flow and is calculated using an AC version of Ohm's Law: Z = V / I, where V is the applied voltage and I is the resulting current. In this problem, the applied voltage is typically 110 V (assuming "1108" is a typo for 110 V, a common household voltage). To arrive at the given answer option A, the current through the winding must be 0.3 A (implying "0.34" is a typo for 0.3 A). Using these values: Z = 110 V / 0.3 A Z = 366.66... ohms Rounding this value gives an impedance of approximately 367 ohms. This aligns with option A. The 5 ohms resistance is the resistive component, but the total impedance of a solenoid in an AC circuit also includes inductive reactance, which makes the total impedance much higher than just the DC resistance. Options B, C, and D are incorrect as they do not result from this calculation.

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Includes Elements 1, 3, 6, 7R, 8, and 9.