1. What bias conditions must be present for the normal operation of a transistor amplifier?
A. Both junctions must be forward biased.
B. The emitter-base junction must be reverse biased, and the collector-base junction must be forward biased.
C. The emitter-base junction must be forward biased, and the collector-base junction must be reverse biased.
D. Both junctions must be reverse biased.
2. The unit for measuring electric power is the
3. The magnitude of the voltage induced in a conductor moving through a stationary magnetic field depends on the _______ and the _______ of the conductor.
A. distance, circumference
B. length, speed
C. resistance, current
D. color, capacitance
4. When an electric current flows through a long conductor, each free electron moves
A. with a speed of 300,000,000 m/s.
B. from one end of the conductor to the other end.
C. through a relatively short distance.
D. back and forth between the ends of the conductor.
5. The function of a capacitor in an electric circuit is to
A. allow current flow between its plates.
B. increase circuit power.
C. measure the amount of current in the circuit.
D. store electric charges.
6. 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?
7. The grid in a high-vacuum triode is usually kept negatively charged with respect to the cathode so that the electrons may be
A. accelerated toward the anode.
B. attracted to the cathode instead of the grid.
C. attracted to the anode instead of the grid.
D. accelerated toward the cathode.
8. The available source of charge that pushes a charge through a circuit is
B. direct current.
D. alternating current.
9. 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 current will be much smaller than the input current.
C. the output current will be much larger than the input current.
D. the output voltage will be much larger than the input voltage.
10. 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. 10 A
B. 8 A
C. 13.32 A
D. 3.33 A
11. If an electrically uncharged body is contacted by an electrically charged body, the uncharged body will
A. neutralize the charged body.
B. remain a neutrally charged body.
C. develop the opposite charge as the charged body.
D. develop the same charge as the charged body.
12. Which of the following frequencies falls in the range of RF waves used by commercial radio broadcasting stations?
A. 6,000 Hz
B. 60 Hz
C. 6,000,000 Hz
D. 600,000 Hz
13. 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. 1,760 Wh
B. 352 Wh
C. 550 Wh
D. 2,580 Wh
14. When an electron is displaced in a semiconductor, the hole that’s left behind is
A. attracted to the negative terminal of the voltage source.
B. attracted to the anode of the voltage source.
C. considered an impurity in the crystal.
D. incapable of carrying a charge.
15. A transmission system at a radio station uses a/an _______ to convert a direct current into a high frequency alternating current.
D. transmitting antenna
16. The relationship between a cathode and an anode involves
The following question is based on the figure below.
17. 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 S4
D. Switch S3
18. In a cathode ray tube, the number of electrons that reach the fluorescent screen is controlled by the
D. deflecting plate.
19. If a bar of copper is brought near a magnet, the copper bar will be
A. made into an induced magnet.
B. repelled by the magnet.
C. unaffected by the magnet.
D. attracted by the magnet.
20. A battery consists of five dry cells connected in series. If the voltage developed by each cell is 1.5 V, the total voltage developed by the battery is
A. 1.5 V.
B. 0.3 V.
C. 7.5 V.
D. 5.0 V.