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?

Related Mcqs:

1. The frequency of an alternating current is____________?

   A. the speed with which the alternator runs
   B. the number of cycles generated in one minute
   C. the number of waves passing through a point in one second
   D. the number of electrons passing through a point in one second

2. What will be the phase angle between two alternating waves of equal frequency, when one wave attains maximum value the other is at zero value________ ?

   A. 0°
   B. 45°
   C. 90°
   D. 180°

3. The r.m.s. value of alternating current is given by steady (D.C.) current which when flowing through a given circuit for a given time produces__________?

   A. the more heat than produced by A.C. when flowing through the same circuit
   B. the same heat as produced by A.C. when flowing through the same circuit
   C. the less heat than produced by A.C. flowing through the same circuit
   D. none of the above

4. In the case of an unsymmetrical alternating current the average value must always be taken over__________?

   A. unsymmetrical part of the wave form
   B. the quarter cycle
   C. the half cycle
   D. the whole cycle

5. When an alternating current passes through an ohmic resistance the electrical power converted into heat is__________?

   A. apparent power
   B. true power
   C. reactive power
   D. none of the above

6. Capacitive reactance is more when_______?

   A. capacitance is less and frequency of supply is less
   B. capacitance is less and frequency of supply is more
   C. capacitance is more and frequency of supply is less
   D. capacitance is more and frequency of supply is more

7. A sine wave has a frequency of 50 Hz. Its angular frequency is ________ radian/second.

   A. 100 n
   B. 50 jt
   C. 25 JT
   D. 5 n

8. In each of the three coils of a three phase generator, an alternating voltage having an r.m.s. value of 220 V is induced. Which of the following values is indicated by the voltmeters ______?

   A. 220 V
   B. 220V3V
   C. 220/V3 V
   D. none of the above

9. In a pure capacitive circuit if the supply frequency is reduced to 1/2, the current will__________?

   A. be reduced by half
   B. be doubled
   C. be four times at high
   D. be reduced to one fourth

10. In a pure inductive circuit if the supply frequency is reduced to 1/2, the current will__________?

    A. be reduced by half
    B. be doubled
    C. be four times as high
    D. be reduced to one fourth