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A capacitor with reactance X_C = 10 ohm and an inductor with reactance X_L = 5 ohm are connected in parallel across an AC voltage source V = 100 V. Find the ratio of the current through the inductor to the total current drawn from the source.
- 1: 2
- 2: 1
- 1: 1
- 2: 3
Correct answer: 2: 1
Solution
Current through inductor I_L = 100/5 = 20 A. Current through capacitor I_C = 100/10 = 10 A. In a parallel LC circuit these currents are 180 deg out of phase, so total source current I = |I_L - I_C| = |20 - 10| = 10 A. Ratio I_L: I = 20: 10 = 2: 1.
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