Please answer all questions.
 |
| 1 | |
A coil has resistance of 20 W and inductance of 0.35 H. Compute its inductive reactance and its impedance to an alternating current of 25 cycles/s. |
| | A) | 55 W, (b) 59 W |
| | B) | 2.2 W, (b) 75 W |
| | C) | 157 W, (b) 3425 W |
| | D) | 0.018 W, (b) 51 W |
|
|
|
| 2 | |
A coil has an inductance of 0.100 H and resistance of 12.0 W. It is connected to a 110-V rms, 60.0-Hz line. Determine (a) the inductive reactance of the coil, (b) the impedance of the coil, (c) the rms current through the coil, (d) the phase angle between current and supply voltage. |
| | A) | (a) 377 W (b) 49.7 W (c) 2.92 A (d) voltage leads by 17.7° |
| | B) | (a) 0.027 W (b) 1565 W (c) 9.17 A (d) voltage leads by 3.14° |
| | C) | (a) 37.7 W (b) 39.6 W (c) 2.78 A (d) voltage leads by 72.3° |
| | D) | (a) 0.628 W (b) 35.7 W (c) 4356 A (d) voltage lags by 72.3° |
|
|
|
| 3 | |
A 10.0-mF capacitor is in series with a 40.0-W resistance, and the combination is connected to a 110-V rms, 60.0-Hz line. Calculate (a) the capacitive reactance, (b) the impedance of the circuit, (c) the rms current in the circuit, (d) the phase angle between current and supply voltage. |
| | A) | (a) 0.0038 W (b) 305 W (c) 0.415 A (d) voltage lags by 8.58° |
| | B) | (a) 265 W (b) 268 W (c) 0.41 A (d) voltage lags by 81.4° |
| | C) | (a) 2.65 mW (b) 72 kW (c) 2.75 A (d) voltage lags by 6.63° |
| | D) | (a) 16 kW (b) 262 W (c) 0.256 MA (d) voltage leads by 81.4° |
|
|
|
| 4 | |
A circuit having a resistance, an inductance, and a capacitance in series is connected to a 110-V rms ac line. For the circuit, R=9.0 W, XL=28 W, and Xc=16 W. Compute (a) the impedance of the circuit, (b) the current, (c) the phase angle between the rms current and supply voltage. |
| | A) | (a) 15 W (b) 7.3 A (c) voltage leads by 53° |
| | B) | (a) 33.5 W (b) 12.2 A (c) voltage leads by 37° |
| | C) | (a) 225 W (b) 0.49 A (c) voltage leads by 6.3° |
| | D) | (a) 45 W (b) 1650 A (c) voltage lags by 53° |
|
|
|
| 5 | |
An experimenter has a coil of inductance 3.0 mH and wishes to construct a circuit whose resonant frequency is 1.0 MHz. What should be the value of the capacitor used? |
| | A) | 8.4 F |
| | B) | 8.4 mF |
| | C) | 0.025 pF |
| | D) | 8.4 pF |
|
|
|
| 6 | |
A circuit has a resistance of 11 W, a coil with an inductive reactance of 120 W, and a capacitor with a 120-W reactance, all connected in series with a 110-V rms, 60-Hz power source. What is the rms potential difference across each circuit element? |
| | A) | (a) VR = 110 V, (b) VL = VC = 1.2 kV |
| | B) | (a) VR = 120 V, (b) VL = VC = 2.4 kV |
| | C) | (a) VR = 4.8 V, (b) VL = VC = 0 kV |
| | D) | (a) VR = 5.0 V, (b) VL = VC = .83 mV |
|
|
|
| 7 | |
An rms current of 30 mA flows through a 4.0-mF capacitor connected across an alternating current line having a frequency of 500 Hz. Compute the reactance of the capacitor and the rms voltage across the capacitor. |
| | A) | (a) 0.32 milliohm, (b) 0.38 mV |
| | B) | (a) 2.0 milliohm, (b) 2400 V |
| | C) | (a) 0.013 ohm, (b) .12 mV |
| | D) | (a) 80 ohm, (b) 2.4 V |
|
|
|
| 8 | |
A coil of negligible resistance is connected in series with a 90-W resistor across a 120-V rms, 60-Hz line. A voltmeter reads 36 V rms across the resistance. Find the rms voltage across the coil and the inductance of the coil. |
| | A) | (a) 114 V, (b) 0.76 H |
| | B) | (a) 84 V, (b) 4.8 H |
| | C) | (a) 156 V, (b) 46 H |
| | D) | (a) 120 V, (b) 0.12 H |
|
|
.