47. Which of the following can vary with ac, but not with dc?
Voltage
Power
Magnitude
Frequency
48. Two waves have the same frequency but differ in phase by 1/20 of a cycle. The phase difference in degrees is _____. Hint: 1 cycle is equal to 360 degrees.
20
36
5.73
18
49,.
If two waves have the same frequency and the same amplitude, but opposite phase (phase difference is 180 degrees), the composite wave (sum of the waves) is:
Half the amplitude of either wave alone.
Zero
Twice the amplitude of either wave alone.
A complex waveform, but with the same frequency as the originals.
50.
In a 117-V utility circuit, the peak voltage is:
234 V
331 V
165 V
82.7 V