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AC Fundamentals Online Quiz practies questions test1
AC Fundamentals Online Quiz practies questions test1
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1. A sine wave has a frequency of 50 Hz. Its angular frequency is _______ radian/second.
100 n
50 jt
25 JT
5 n
2. The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes_____ohms.
2.5
5
10
15
3. The period of a wave is ______.
the same as frequency
time required to complete one cycle
expressed in amperes
none of the above
4. The form factor is the ratio of _____.
peak value to r.m.s. value
r.m.s. value to average value
average value to r.m.s. value
none of the above
5. The period of a sine wave is 1 / 50 seconds. Its frequency is ______.
20 Hz
30 Hz
40 Hz
50 Hz
6. A heater is rated as 230 V, 10 kW, A.C. The value 230 V refers to _____.
average voltage
r.m.s. voltage
peak voltage
none of the above
7. If two sinusoids of the same frequency but of different amplitudes and phase angles are subtracted, the resultant is _____.
a sinusoid of the same frequency
a sinusoid of half the original frequency
a sinusoid of double the frequency
not a sinusoid
8. The peak value of a sine wave is 200 V. Its average value is ______.
127.4 V
141.4 V
282.8 V
200 V
9. If two sine waves of the same frequency have a phase difference of JT radians, then ______.
both will reach their minimum values at the same instant
both will reach their maximum values at the same instant
when one wave reaches its maxi¬mum value, the other will reach its minimum value
none of the above
10. The voltage of domestic supply is 220V. This figure represents ______.
mean value
r.m.s. value
peak value
average value
11. Two waves of the same frequency have opposite phase when the phase angle between them is _____.
360°
180°
90°
0°
12. The power consumed in a circuit element will be least when the phase difference between the current and voltage is _____.
180°
90°
60°
0°
13. The r.m.s. value and mean value is the same in the case of _____.
triangular wave
sine wave
square wave
half wave rectified sine wave
14. For the same peak value which of the following wave will 'have the highest r.m.s. value ?
square wave
half wave rectified sine wave
triangular wave
sine wave
15. For the same peak value, which of the following wave has the least mean value ?
half wave rectified sine wave
triangular wave
sine wave
square wave
16. For a sine wave with peak value Imax the r.m.s. value is ______.
0.5 Imax
0.707
0.9
1.414 Lmax
17. Form Factor is the ratio of ______.
average value/r.m.s. value
average value/peak value
r.m.s. value/average value
r.m.s. value/peak value
18. Form factor for a sine wave is _____.
1.414
0.707
1.11
0.637
19. For a sine wave with peak value Emax______8.30. the average value is
0.636 Emax
0.707 Emax
0.434 EWc
lAUEmax
20. For a frequency of 200 Hz, the time period will be _____.
0.05 s
0.005 s
0.0005 s
0.5 s
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