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Unformatted text preview: howard (cah3459) – ohw23 – turner – (56705) 1 This printout should have 20 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 (part 1 of 2) 10.0 points When a particular inductor is connected to a sinusoidal voltage with a 232 V amplitude, a peak current of 5 . 8 A appears in the inductor. What is the maximum current if the fre quency of the applied voltage is doubled? Correct answer: 2 . 9 A. Explanation: Let : I max = 5 . 8 A . The current in the circuit is I max = V max X L = V max ω L . When the frequency is doubled, the current is I new = V max 2 ω L = 1 2 I max = 1 2 5 . 8 A = 2 . 9 A . 002 (part 2 of 2) 10.0 points What is the inductive reactance at the new frequency? Correct answer: 80 Ω. Explanation: The inductive reactance is X L,new = V max I new = 232 V 2 . 9 A = 80 Ω . 003 (part 1 of 2) 10.0 points An electric stove is connected to an AC source with rms voltage of 240 V . Find the maximum voltage supplied to the stove when it is operating. Correct answer: 339 . 411 V. Explanation: The rms voltage is V rms = 1 √ 2 V max , So the maximum supplied voltage is V max = √ 2 V rms = √ 2 (240 V) = 339 . 411 V . 004 (part 2 of 2) 10.0 points The resistance of the stove’s elements is 12 . 8 Ω. What rms current flows through it? Correct answer: 18 . 75 A. Explanation: Let : R = 12 . 8 Ω . The rms current is I rms = V rms R = 240 V 12 . 8 Ω = 18 . 75 A . 005 10.0 points Alternating current in the United States has a frequency of 1. 240 hertz. 2. 30 hertz. 3. 60 hertz. correct 4. 120 hertz....
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This note was uploaded on 11/28/2010 for the course PHY 56705 taught by Professor Turner during the Spring '10 term at University of Texas at Austin.
 Spring '10
 Turner

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