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# practicefinal - Name: _ Class: _ Date: _ ID: A Final Exam...

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Name: ________________________ Class: ___________________ Date: __________ ID: A 1 Final Exam Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. Constants k o = 9.0x10 9 N m 2 /C 2 , µ o = 4 π x10 -7 T m/A , ε o = 8.8x10 -12 C 2 /Nm 2 , g =9.8 m/s 2 L f (water) = 334 kJ/kg, c(water) =4.2 kJ/kg ____ 1. The impedance of a 120 resistor, a 33 µ F capacitor, and an 80 mH inductor in series and connected across a 115 V ac wall outlet is: a. 60 b. 80 c. 120 d. 130 e. None of the above ____ 2. In an LRC circuit used for tuning the 95.3 MHz FM radio station the value of the resistor is 2.8 and the inductor has a value of 1.6 H. The value of the capacitor in the circuit is: a. 1.7 pF b. 2.4 pF c. 4.2 pF d. 6.1 pF e. None of the above ____ 3. A series circuit with R = 96 , L = 16 mH, and C = 4.0 F is connected to a 12 V (peak value) AC source with variable frequency. What is the rms current in the circuit at the resonance frequency? a. 63 mA b. 88 mA c. 0.28 A d. 0.35 A e. None of the above ____ 4. A sinusoidal current flows through an LC circuit at the resonance frequency. When the current is zero the absolute value of the voltage across the capacitor is __________ and the energy in the circuit is stored in the _____________ field. a. maximum, magnetic b. maximum, electric c. zero, magnetic d. zero, electric e. none of the above ____ 5. In a transformer the number of turns in the primary is 200 and the number of turns in the secondary is 20. An ac voltage of 120 volts and 1.0 amps is applied to the primary. The output from the secondary is ____ volts and ______ amps. (ignore losses). a. 20, 6 b. 6, 20 c. 12,10 d. 12, 1 e. none of the above

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ID: A 2 ____ 6. An engine has a maximum theoretical efficiency of 36%. The temperature difference between the input and the output is 432ºC. The temperature of the exhaust is: a. 840º K b. 768º K c. 645º K d. 447º K e. None of the above ____ 7. Two charges of +5.0 µ C each are placed on two corners of an equilateral triangle of side 0.50 m. The magnitude of the electric field at the third corner is: a. 3.9 × 10 3 N/C b. 2.8 × 10 4 N/C c. 1.6 × 10 5 N/C d. zero e. None of the above ____ 8. Two capacitors of 80 F and 40 F are separately charged to 200 C and 80 C , respectively. They are then connected in parallel so that the + plate of one goes to the - plate of the other , and vise versa. The final voltage across the two capacitors is: a. 0.80 V b. 1.0 V c. 1.4 V d. 3.2 V e. None of the above ____ 9. A 1500 W room heater is used for 12 hours. At \$0.085 per kilowatt-hour, the cost of operating the heater is: a. \$3.24 b. \$2.35 c. \$1.53 d. \$1.12 e. None of the above ____ 10. Two resistors, 6.0 and 9.0 connected in parallel, are in series with another combination of two resistors, 8.0 d. 9.3 W e. None of the above
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## This note was uploaded on 01/24/2010 for the course PHYS 1 taught by Professor Onuich during the Spring '07 term at CSU Northridge.

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practicefinal - Name: _ Class: _ Date: _ ID: A Final Exam...

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