1. A circuit contains two devices that are connected in parallel. If the resista
ID: 1352802 • Letter: 1
Question
1. A circuit contains two devices that are connected in parallel. If the resistance of one of these devices is 12 ohms and the resistance of the other device is 4 ohms, the total resistance of the two devices is A. 0.0625 ohms. B. 16 ohms. C. 3 ohms. D. 0.333 ohms. 2. Suppose that you're facing a straight current-carrying conductor, and the current is flowing toward you. The lines of magnetic force at any point in the magnetic field will act in A. the direction opposite to the current. B. a clockwise direction. C. a counterclockwise direction. D. the same direction as the current. 3. A body that offers little resistance to the movement of free electrons from one point to another is a/an A. coulomb. B. conductor. C. capacitor. D. insulator. 4. When an electron is displaced in a semiconductor, the hole that's left behind is A. attracted to the anode of the voltage source. B. incapable of carrying a charge. C. attracted to the negative terminal of the voltage source. D. considered an impurity in the crystal. 5. A transformer has a primary voltage of 115 V and a secondary voltage of 24 V. If the number of turns in the primary is 345, how many turns are in the secondary? A. 8 B. 690 C. 72 D. 1,653 6. When an electric current flows through a long conductor, each free electron moves A. with a speed of 300,000,000 m/s. B. back and forth between the ends of the conductor. C. through a relatively short distance. D. from one end of the conductor to the other end. 7. A complete circuit contains two parallel-connected devices and a generator for providing the electromotive force. The resistance of the first device is 12 ohms, the resistance of the second device is 4 ohms, and the voltage developed by the generator is 40 V. What is the magnitude of the current flowing through the first device? A. 3.33 A B. 8 A C. 13.32 A D. 10 A The following question is based on the figure below. 8. If you want to stop the current flow through Device 3 in the circuit shown above, which one of the following single switches should you open? A. Switch S2 B. Switch S5 C. Switch S3 D. Switch S4 9. The unit for measuring electric power is the A. volt. B. ohm. C. ampere. D. watt. 10. Which of the following frequencies falls in the range of RF waves used by commercial radio broadcasting stations? A. 60 Hz B. 6,000 Hz C. 600,000 Hz D. 6,000,000 Hz 11. A body that has relatively few free electrons and offers comparatively great resistance to the movement of free electrons is a/an A. coulomb. B. insulator. C. conductor. D. capacitor. 12. The relationship between a cathode and an anode involves A. protons. B. electrons. C. neutrons. D. diodes. 13. If the resistance of an electric circuit is 12 ohms and the voltage in the circuit is 60 V, the current flowing through the circuit is A. 5 A. B. 720 A. C. 60 A. D. 0.2 A. 14. When all parts of a circuit are composed of conducting materials, the circuit is said to be A. parallel. B. shorted. C. closed. D. open. 15. The function of a capacitor in an electric circuit is to A. allow current flow between its plates. B. increase circuit power. C. store electric charges. D. measure the amount of current in the circuit. 16. The ability to regulate the amount of charge flowing in a circuit is A. resistance. B. alternating current. C. direct current. D. voltage. 17. What bias conditions must be present for the normal operation of a transistor amplifier? A. The emitter-base junction must be reverse biased, and the collector-base junction must be forward biased. B. Both junctions must be reverse biased. C. Both junctions must be forward biased. D. The emitter-base junction must be forward biased, and the collector-base junction must be reverse biased. 18. An electric heating element is connected to a 110 V circuit and a current of 3.2 A is flowing through the element. How much energy is used up during a period of 5 hours by the element? A. 352 Wh B. 550 Wh C. 1,760 Wh D. 2,580 Wh 19. The available source of charge that pushes a charge through a circuit is A. resistance. B. voltage. C. direct current. D. alternating current. 20. An example of an atom that has no charge is one that has A. 3 protons, 1 electron, and 3 neutrons. B. 2 protons, 2 electrons, and 1 neutron. C. 3 protons, 2 electrons, and 1 neutron. D. 1 proton, 2 electrons, and 3 neutrons. 21. The part of the atom that accounts for electricity is the A. nucleus. B. proton. C. electron. D. neutron. 22. A PNP transistor is connected in a circuit so that the collector-base junction remains reverse biased and the emitter-base junction is forward biased. This transistor can be used as a power amplifier because A. the output voltage will be much smaller than the input voltage. B. the output voltage will be much larger than the input voltage. C. the output current will be much larger than the input current. End of exam D. the output current will be much smaller than the input current. 23. If an electrically uncharged body is contacted by an electrically charged body, the uncharged body will A. develop the opposite charge as the charged body. B. neutralize the charged body. C. develop the same charge as the charged body. D. remain a neutrally charged body. 24. If one body is positively charged and another body is negatively charged, free electrons tend to A. move from the positively charged body to the negatively charged body. B. move from the negatively charged body to the positively charged body. C. remain in the positively charged body. D. remain in the negatively charged body. 25. To use your left hand to determine the direction of the voltage developed in a moving conductor in a stationary magnetic field, you must point your A. thumb in the direction of the magnetic flux. B. forefinger in the direction of the motion. C. forefinger in the direction of the lines of force. D. thumb in the direction of the electromagnetic force.
*NB: Ignore number 7
Explanation / Answer
We know that for parallel resistants we have:
1/Rtotal=1/R1+1/R2
1/Rtotal=1/12+1/4=4/12=1/3
Rtotal=3 ohms
2)clock wise direction. For the right hand rule we can reach the answer.
3)A conductor is an electrical path which offers comparatively little resistance. Some examples are silver, copper, aluminum, zinc, brass, platinum etc
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