AC Fundamentals

#1. In a pure inductor the voltage wave form leads the current by...?

120*

60*

90*

180*

#2. The form factor of sinusoidal wave form is....?

1.11

3.14

1.57

1.414

#3. The instataneous voltage across a pure resistor is.... with current?

out of phase

leads

in phase

lags

#4. The reciprocal of frequency is known as....?

amplitude

resonance

time period

time constant

#5. Reactive power is given by....?

VI Cos$

VI Sin $

VIR

VI

#6. Form factor is the ratio of....?

instantaneous value x rms value

rms value / average value

average value x rms value

average value / rms value

#7. The power factor of the inductive loading is....?

zero

unity

leading

lagging

#8. Impedance at series resonance circuit is....?

minimum

maximum

none of the above

average

#9. Power factor is defined as....?

kVA/kW

kVAR/kVA

kW/kVA

kW/kVR

#10. In a AC series circuits Q factor is....?

cos$

1/cos$

1/sin$

sin$

#11. Power factor of R-C series circuit is.....?

0

1

greater than 1

between 0 and 1

#12. Capacitive reactance is......?

directly proportional to frequency

inversely proportional to frequency

independent of frequency

directly proportional to capacitance

#13. The ratio of Z/R is.....?

form factor

power factor

reciprocal of power factor

reciprocal of form factor

#14. Admittance is the reciprocal of....?

resistance

impedence

reactance

susceptance

#15. The power factor of ordinary electric bulb is...?

slightly more than one

slightly less than one

one

zero

#16. Unit of inductive reactance is....?

ohm

hentry

milli hentry

weber

#17. Peak factor of a sinusoidal wave form is....?

1.11

1.21

1.41

1

#18. The rms value of a sine wave is 100A. Its peak value is...?

200 A

141 A

160 A

100 A

#19. The power factor of an AC circuit is equal to.....?

cosine of the phase angle

unity for a resistive circuit

one

sine of the phase angle

#20. Unit of reactive power is....?

ohm

VA

watt

VAR

#21. With in the increase in applied frequency, the dielectric loss will be....?

one half

same

increase

decrease

#22. With in the increase in applied frequency, the dielectric loss will be....?

one half

same

decrease

increase

#23. Q factor of a series R-L-C circuit possessing resonant frequency of 10 Hz and band width of 5 Hz is...?

4

2

5.5

2.5

#24. Power factor of an inductive circuit is usually improved by adding a capacitor to it in....?

series

either in series or parallel

parallel

#25. Form factor of a full rectified sine wave is...?

1.571

1.11

1.41

1

#26. Form factor of a half rectified sine wave is...?

1

1.571

1.11

1.41

rms / average = (Vm/2)/(Vm/pi) = 1.571

#27. An alternating current is given by i=14.14sin377t. find its rms value of current?

15 A

10 A

24 A

14.14 A

14.14/1.4 = 10A

#28. The ratio of maximum value to the rms value of an alternating quantity is called....?

average value

mean value

form factor

peak factor

#29. A seris RL circuit has a resistance of 30 ohms and an inductance of 40 ohms. The impedence is....?

40 ohms

90 ohms

50 ohms

70 ohms

Root of 900 1600 = 50

#30. The unit of capacitance is....?

watt

hentry

farad

ohm

#31. Two capacitors of 8 micro farad each are connected in series. the total capacitance is....?

4 mF

16 mF

10 mF

8 mF

8/2=4

#32. Capacitance is not affected by...?

plate area

dielectric material

distance between plates

frequency

#33. Two capacitors of 10 micro farad each are connected in parallel. the total capacitance is....?

5 mF

10 mF

100 mF

20 mF

#34. The capacitors opposition to alternating current is called...?

capacitive reactance

impedence

capacitance

resistance

#35. In a capacitive AC circuit is the.....?

none of the above

current leads voltage

current is inphase with voltage

current laggs voltage

#36. Which condition is called as resonance RLC circuit?

XL= XC

XL< XC

XL > XC

#37. The line voltage in three phase delta connection is....?

Thrice as phase voltage

same as the phase voltage

none of these

Twice as phase voltage

#38. The line current in three phase star connection is....?

none of these

Twice as phase current

Thrice as phase current

same as the phase current

#39. Potential inside a hollow sphere charged with a voltage V is....?

0

V/2

V

2V

#40. The reciprocal of impedance is...?

conductance

susceptance

admittance

resistance

#41. Phase sequence is the order of attaining?

Maximum value

None of the above

RMS value

Average value

#42. In a R.L.C series resonant circuit....?

R=Z

R=XC

XL>XC

R=XL

#43. Two possible phase sequences are....?

RYB,YBR

RBY,YRB

RYB,RBY

BRY,RYB

#44. In a RLC resonant circuit magnification is.....?

WL/R

WLC

WL

Z

#45. Three phase inter connection used in 3 phase 4 wire distribution system is.....?

star star

delta delta

delta

star

AC Fundamentals

Results

#1. In a pure inductor the voltage wave form leads the current by...?

#2. The form factor of sinusoidal wave form is....?

#3. The instataneous voltage across a pure resistor is.... with current?

#4. The reciprocal of frequency is known as....?

#5. Reactive power is given by....?

#6. Form factor is the ratio of....?

#7. The power factor of the inductive loading is....?

#8. Impedance at series resonance circuit is....?

#9. Power factor is defined as....?

#10. In a AC series circuits Q factor is....?

#11. Power factor of R-C series circuit is.....?

#12. Capacitive reactance is......?

#13. The ratio of Z/R is.....?

#14. Admittance is the reciprocal of....?

#15. The power factor of ordinary electric bulb is...?

#16. Unit of inductive reactance is....?

#17. Peak factor of a sinusoidal wave form is....?

#18. The rms value of a sine wave is 100A. Its peak value is...?

#19. The power factor of an AC circuit is equal to.....?

#20. Unit of reactive power is....?

#21. With in the increase in applied frequency, the dielectric loss will be....?

#22. With in the increase in applied frequency, the dielectric loss will be....?

#23. Q factor of a series R-L-C circuit possessing resonant frequency of 10 Hz and band width of 5 Hz is...?

#24. Power factor of an inductive circuit is usually improved by adding a capacitor to it in....?

#25. Form factor of a full rectified sine wave is...?

#26. Form factor of a half rectified sine wave is...?

#27. An alternating current is given by i=14.14sin377t. find its rms value of current?

#28. The ratio of maximum value to the rms value of an alternating quantity is called....?

#29. A seris RL circuit has a resistance of 30 ohms and an inductance of 40 ohms. The impedence is....?

#30. The unit of capacitance is....?

#31. Two capacitors of 8 micro farad each are connected in series. the total capacitance is....?

#32. Capacitance is not affected by...?

#33. Two capacitors of 10 micro farad each are connected in parallel. the total capacitance is....?

#34. The capacitors opposition to alternating current is called...?

#35. In a capacitive AC circuit is the.....?

#36. Which condition is called as resonance RLC circuit?

#37. The line voltage in three phase delta connection is....?

#38. The line current in three phase star connection is....?

#39. Potential inside a hollow sphere charged with a voltage V is....?

#40. The reciprocal of impedance is...?

#41. Phase sequence is the order of attaining?

#42. In a R.L.C series resonant circuit....?

#43. Two possible phase sequences are....?

#44. In a RLC resonant circuit magnification is.....?

#45. Three phase inter connection used in 3 phase 4 wire distribution system is.....?

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