Frequency and Wavelength

Review Questions

1. What is the name of a current that flows only in one direction?

A. An alternating current
B. A direct current
C. A normal current
D. A smooth current

2. Which of the following will produce a direct current (DC)?

A. A NiCd battery
B. An RF signal generator
C. A commercial generating station
D. A crystal calibrator

3. What is the name of a current that flows back and forth, first in one direction, then in the opposite direction?

A. An alternating current
B. A direct current
C. A rough current

4. Which of the following will produce an alternating current (AC)?

B. A solar array
C. A fuel cell
D. A commercial generating station

5. What term means the number of times per second that an alternating current flows back and forth?

A. Pulse rate
B. Speed
C. Wavelength
D. Frequency

6. What is the basic unit of frequency?

A. The hertz
B. The watt
C. The ampere
D. The ohm

7. What does 60 hertz (Hz) mean?

A. 6000 cycles per second
B. 60 cycles per second
C. 6000 meters per second
D. 60 meters per second

8. Most humans can hear sounds in what frequency range?

A. 0 - 20 Hz
B. 20 - 20,000 Hz
C. 200 - 200,000 Hz
D. 10,000 - 30,000 Hz

9. Why do we call electrical signals in the frequency range of 20 Hz to 20,000 Hz audio frequencies?

A. Because the human ear cannot sense anything in this range
B. Because the human ear can sense sounds in this range
C. Because this range is too low for radio energy
D. Because the human ear can sense radio waves in this range

10. What is the lowest frequency of electrical energy that is usually known as a radio frequency?

A. 20 Hz
B. 2,000 Hz
C. 20,000 Hz
D. 1,000,000 Hz

11. What is the name for the distance an AC signal travels during one complete cycle?

A. Wave speed
B. Waveform
C. Wavelength

12. What happens to a signal's wavelength as its frequency increases?

A. It gets shorter
B. It gets longer
C. It stays the same
D. It disappears

13. What happens to a signal's frequency as its wavelength gets longer?

A. It goes down
B. It goes up
C. It stays the same
D. It disappears

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