Alternating Current and Voltage MCQ Test

Practice Test: Question Set - 03


1. A 20 kHz pulse waveform consists of pulses that are 15 μs wide. The duty cycle
    (A) Is 1%
    (B) Is 30%
    (C) Is 100%
    (D) Cannot be determined

2. The designation rms means repetitions measured per second.
    (A) True
    (B) False

3. The average value of a 12 V peak sine wave over one complete cycle is
    (A) 0 V
    (B) 1.27 V
    (C) 7.64 V
    (D) 6.37 V

4. A square wave has a period of 60 μs. The first odd harmonic is
    (A) 5 kHz
    (B) 50 kHz
    (C) 500 kHz
    (D) 33.33 kHz

5. A sine wave with a period of 4 ms is changing at a faster rate than a sine wave with a period of
    (A) 0.0045 s
    (B) 2 ms
    (C) 1.5 ms
    (D) 3,000 μs

6. Two series resistors are connected to an ac source. If there are 7.5 V rms across one resistor and 4.2 V rms across the other, the peak source voltage is
    (A) 16.54 V
    (B) 1.65 V
    (C) 10.60 V
    (D) 5.93 V

7. A waveform has a baseline of 3 V, a duty cycle of 20%, and an amplitude of 8 V. The average voltage value is
    (A) 4 V
    (B) 4.6 V
    (C) 1.6 V
    (D) 11 V

8. A signal with a 400 μs period has a frequency of
    (A) 250 Hz
    (B) 2,500 Hz
    (C) 25,000 Hz
    (D) 400 Hz

9. Average value of a sine wave is 0.707 times the peak value.
    (A) True
    (B) False

10. A saw-tooth wave has a period of 10 ms. Its frequency is
    (A) 10 Hz
    (B) 50 Hz
    (C) 100 Hz
    (D) 1,000 Hz

11. The length of a phasor represents the amplitude.
    (A) True
    (B) False

12. A phasor represents
    (A) The magnitude and a quantity direction
    (B) The width of a quantity
    (C) The phase angle
    (D) The magnitude of a quantity

13. A 1 kHz signal has a period of 1 ms.
    (A) True
    (B) False

14. The average half-cycle value of a sine wave with a 40 V peak is
    (A) 25.48 V
    (B) 6.37 V
    (C) 14.14 V
    (D) 50.96 V

15. Duty cycle is the characteristic of a pulse waveform that indicates the high time versus the low time.
    (A) True
    (B) False

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