Expert: Steve Johnson - 6/21/2006

Question
COULD YOU CHECK MY ANSWERS ON THSES QUESTIONS AND SE IF I DID THEM RIGHT DID WAS HARD FOR ME.THE ANSWERS ARE BELOW FOR THEM.


1. If one body is positively charged and another body is negatively charged, free electrons tend to

  A. move from the negatively charged body to the positively charged body.
   B. move from the positively charged body to the negatively charged body.
   C. remain in the negatively charged body.
   D. remain in the positively charged body.
       
    
2. 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. 0.3 V.
   B. 1.5 V.
   C. 5.0 V.
   D. 7.5 V.
       
    
3. 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. accelerated toward the cathode.
   C. attracted to the anode instead of the grid.
   D. attracted to the cathode instead of the grid.
       
    
4. An example of an atom that has no charge is one that has

  A. 2 protons, 2 electrons, and 1 neutron.
   B. 1 proton, 2 electrons, and 3 neutrons.
   C. 3 protons, 1 electron, and 3 neutrons.
   D. 3 protons, 2 electrons, and 1 neutron.
       
    
5. 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. remain a neutrally charged body.
   C. develop the same charge as the charged body.
   D. neutralize the charged body.
       
    
6. 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. The emitter-base junction must be forward biased, and the collector-base junction must be reverse biased.
   C. Both junctions must be reverse biased.
   D. Both junctions must be forward biased.
       
    
7. When an electric current flows through a long conductor, each free electron moves

  A. from one end of the conductor to the other end.
   B. with a speed of 300,000,000 m/s.
   C. back and forth between the ends of the conductor.
   D. through a relatively short distance.
       
    
8. 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. 0.2 A.
   B. 5 A.
   C. 60 A.
   D. 720 A.
       
    
9. Electrons are emitted from a conductor when the conductor is

  A. exposed to weak light.
   B. cooled rapidly.
   C. bombarded by high-speed electrons.
   D. subjected to a small voltage.
       
    
10. 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. 0.333 ohms.
   C. 3 ohms.
   D. 16 ohms.
       
    
11. When a PNP transistor is connected in a circuit in the manner shown in Figure 52 of Electricity and Electronics, it can be used as a power amplifier because

  A. the output current will be much smaller than the input current.
   B. the output current will be much larger than the input current.
   C. the output voltage will be much smaller than the input voltage.
   D. the output voltage will be much larger than the input voltage.
       
    
12. The function of a capacitor in an electric circuit is to

  A. allow current flow between its plates.
   B. measure the amount of current in the circuit.
   C. increase circuit power.
   D. store electric charges.
       
    
13. In a cathode ray tube, the number of electrons that reach the fluorescent screen is controlled by the

  A. anode.
   B. cathode.
   C. deflecting plate.
   D. grid.
       
    
14. 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
       
    
15. 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. thumb in the direction of the electromagnetic force.
   C. forefinger in the direction of the lines of force.
   D. forefinger in the direction of the motion.
       
       
1A
2D
3C
4A
5B
6C
7C
8D
9C
10D
11C
12D
13A
14D
15C  

Answer
Hello Daniel,

I disagree with you on these.

5. 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. remain a neutrally charged body.
   C. develop the same charge as the charged body.
   D. neutralize the charged body.

The 2 bodies will share the excess or shortage of electrons.


6. 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. The emitter-base junction must be forward biased, and the collector-base junction must be reverse biased.
   C. Both junctions must be reverse biased.
   D. Both junctions must be forward biased.

I'd prefer to know a bit more about the "transistor amplifier", I'm afraid of a trick, but I think b.


7. When an electric current flows through a long conductor, each free electron moves

  A. from one end of the conductor to the other end.
   B. with a speed of 300,000,000 m/s.
   C. back and forth between the ends of the conductor.
   D. through a relatively short distance.

I've seen this question at least 3 times now since April. I always say d. There are so many free electrons that the individual electrons goes surprisingly slowly.


8. 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. 0.2 A.
   B. 5 A.
   C. 60 A.
   D. 720 A.

I = E/R


10. 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. 0.333 ohms.
   C. 3 ohms.
   D. 16 ohms.

R1*R2/(R1+R2)


 11. When a PNP transistor is connected in a circuit in the manner shown in Figure 52 of Electricity and Electronics, it can be used as a power amplifier because

  A. the output current will be much smaller than the input current.
   B. the output current will be much larger than the input current.
   C. the output voltage will be much smaller than the input voltage.
   D. the output voltage will be much larger than the input voltage.

Amplifiers usually make something bigger.  I haven't seen the figure, but should be b or d.


14. 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

The FM dial on my radio covers 88-108 MHz
The AM dial on my radio covers 550-1600 KHz.

I hope this helps,
Steve