Physics for Scientists and Engineers 8ed - ch33 - end of chapter questions

Physics for Scientists and Engineers 8ed - ch33 - end of chapter questions

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Questions W denotes answer available in Student SolutionsManual/Study Guide; O denotes objective question 1. O (i) What is the time average of the “square-wave” potential shown in Figure Q33.1? (a) max 2 V (b) V max (c) V max / 2 (d) V max /2 (e) V max /4 (ii) What is the rms voltage? Choose from the same possibilities. 2. O Do AC ammeters and voltmeters read (a) peak- to-valley, (b) maximum, (c) rms, or (d) average values? 3. O A sinusoidally varying potential difference has amplitude 170 V. (i) What is its minimum instantaneous value? (a) 240 V (b) 170 V (c) 120 V (d) 0 (e) - 120 V (f) - 170 V (g) - 240 V (ii) What is its average value? (iii) What is its rms value? Choose from the same possibilities in each case. 4. Why does a capacitor act as a short circuit at high frequencies? Why does it act as an open circuit at low frequencies? 5. Explain how the mnemonic “ELI the ICE man” can be used to recall whether current leads voltage or voltage leads current in RLC circuits. Note that E represents emf ε . 6. Why is the sum of the maximum voltages across each element in a series RLC circuit usually greater than the maximum applied voltage? Doesn’t that inequality violate Kirchhoff’s loop rule? 7. Does the phase angle depend on frequency? What is the phase angle when the inductive reactance equals the capacitive reactance? 8. O (i) When a particular inductor is connected to a source of sinusoidally varying emf with constant amplitude and a frequency of 60 Hz, the rms current is 3 A. What is the rms current if the source frequency is doubled? (a) 12 A (b) 6 A (c) 4.24 A (d) 3 A (e) 2.12 A (f) 1.5 A (g) 0.75 A (ii) Repeat part (i) assuming the load is a capacitor instead of an inductor. (iii) Repeat part (i) assuming the load is a resistor instead of an inductor. 9. O What is the impedance of a series RLC circuit at resonance? (a) X L (b) X C (c) R (d) X L - X C (e) 2 X L (f) 2 R (g) 0 10. O What is the phase angle in a series RLC circuit at resonance? (a) 180° (b) 90° (c) 0 (d) - 90° (e) None of these answers is necessarily correct. 11. A certain power supply can be modeled as a source of emf in series with both a resistance of 10 and an inductive reactance of 5 . To obtain maximum power delivered to the load, it is found that the load should have a resistance of R L = 10 , an inductive reactance of zero, and a capacitive reactance of 5 . (a) With this load, is the circuit in resonance? (b) With this load, what fraction of the average power put out by the source of emf is delivered to the load? (c) To increase the fraction of the power delivered to the load, how could the load be changed? You may wish to review Example 28.2 and Problem 4 in Chapter 28 on maximum power transfer in DC circuits. 12.
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This note was uploaded on 05/22/2010 for the course PHYS 2326 taught by Professor Staff during the Summer '08 term at HCCS.

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Physics for Scientists and Engineers 8ed - ch33 - end of chapter questions

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