a. 64 hertz.
c. 1,024 hertz.
b. 256 hertz.
d. 2,048 hertz.
9. Sounds are made up of fundamental frequencies and their harmonics. The fundamental frequencies
contained in the normal speaking voice have a range of
a. 50 to 200 hertz.
c. 100 to 1,200 hertz.
b. 100 to 300 hertz.
d. 200 to 2,700 hertz.
10. The lungs furnish the power for human speech. The average power necessary for normal conversation is
about
a. 0.1 microwatt.
c.
1,000 microwatts.
b. 10 microwatts.
d.
2,000 microwatts.
11. The ability of the human ear to respond to sound varies with the frequency of the sound wave. Tests with
the audiometer have established that the frequency-of the sound easiest to hear is about
a. 300 hertz.
c. 2,000 hertz.
b. 1,000 hertz.
d. 4,000 hertz.
12. Bell's first telephones used sound-powered transmitters. In addition to the low input power, the most
serious limiting factor to the transmission range of sound-powered transmitters is the
a. lack of amplifying facilities.
b. inflexibility of the diaphragms.
c. inefficiency of permanent magnets.
d. poor quality of the transmission media.
13. The condition of a carbon telephone transmitter can sometimes be determined by measuring its resistance.
The resistance of a new transmitter is approximately
a. 20 ohms.
c. 100 ohms.
b. 35 ohms.
d. 300 ohms.
14. The development of the carbon transmitter greatly increased the transmitting device used by Bell. The
nature of the current through the carbon transmitter during conversation can best be described as
a. an alternating current.
c. a pulsating direct current.
b. a steady direct current.
d. a complex alternating current.
410 L1
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