MCQ – AC Fundamentals Results #1. 1 90* 60* 180* 120* #2. 2 1.11 1.57 3.14 1.414 #3. 3 in phase leads out of phase lags #4. 4 amplitude resonance time constant time period #5. 5 VI Sin $ VIR VI Cos$ VI #6. Form factor is the ratio of….? instantaneous value x rms value average value / rms value rms value / average value average value x rms value #7. The power factor of the inductive loading is….? leading unity lagging zero #8. Impedance at series resonance circuit is….? average maximum minimum none of the above #9. Power factor is defined as….? kW/kVR kVAR/kVA kVA/kW kW/kVA #10. In a AC series circuits Q factor is….? cos$ sin$ 1/sin$ 1/cos$ #11. Power factor of R-C series circuit is…..? between 0 and 1 greater than 1 0 1 #12. Capacitive reactance is……? directly proportional to frequency independent of frequency directly proportional to capacitance inversely proportional to frequency #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….? reactance impedence susceptance resistance #15. The power factor of ordinary electric bulb is…? one slightly more than one slightly less than one zero #16. Unit of inductive reactance is….? weber ohm hentry milli hentry #17. Peak factor of a sinusoidal wave form is….? 1 1.21 1.11 1.41 #18. The rms value of a sine wave is 100A. Its peak value is…? 200 A 160 A 100 A 141 A #19. The power factor of an AC circuit is equal to…..? cosine of the phase angle sine of the phase angle unity for a resistive circuit one #20. Unit of reactive power is….? ohm watt VA VAR #21. With in the increase in applied frequency, the dielectric loss will be….? increase decrease one half same #22. With in the increase in applied frequency, the dielectric loss will be….? same decrease increase one half #23. Q factor of a series R-L-C circuit possessing resonant frequency of 10 Hz and band width of 5 Hz is…? 2 2.5 5.5 4 #24. Power factor of an inductive circuit is usually improved by adding a capacitor to it in….? either in series or parallel series parallel #25. Form factor of a full rectified sine wave is…? 1 1.11 1.41 1.571 #26. Form factor of a full rectified sine wave is…? 1.571 1 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? 10 A 24 A 15 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….? form factor average value mean value peak factor #29. A seris RL circuit has a resistance of 30 ohms and an inductance of 40 ohms. The impedence is….? 50 ohms 70 ohms 40 ohms 90 ohms Root of 900 1600 = 50 #30. The unit of capacitance is….? farad ohm hentry watt #31. Two capacitors of 5 micro farad each are connected in series. the total capacitance is….? 16 mF 4 mF 10 mF 8 mF 8/2=4 #32. Capacitance is not affected by…? distance between plates plate area frequency dielectric material #33. Two capacitors of 10 micro farad each are connected in parallel. the total capacitance is….? 10 mF 100 mF 20 mF 5 mF #34. The capacitors opposition to alternating current is called…? impedence capacitive reactance resistance capacitance #35. In a capacitive AC circuit is the…..? none of the above current laggs voltage current leads voltage current is inphase with 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 Twice as phase voltage same as the phase voltage none of these #38. The line voltage in three phase delta connection is….? Twice as phase current same as the phase current none of these Thrice as phase current #39. Potential inside a hollow sphere charged with a voltage V is….? 0 V V/2 2V #40. The reciprocal of impedance is…? admittance resistance conductance susceptance #41. Phase sequence is the order of attaining? Average value Maximum value RMS value None of the above #42. In a R.L.C series resonant circuit….? XL>XC R=XL R=Z R=XC #43. Two possible phase sequences are….? BRY,RYB RYB,RBY RBY,YRB RYB,YBR #44. In a RLC resonant circuit magnification is…..? WL WLC Z WL/R #45. Three phase inter connection used in 3 phase 4 wire distribution system is…..? star star star delta delta delta Previous Finish
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