MCQOPTIONS
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MCQOPTIONS
This section includes 214 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The r.m.s. value of pure cosine function is_________? |
| A. | 0.5 of peak value |
| B. | 0.707 of peak value |
| C. | same as peak value |
| D. | zero |
| Answer» C. same as peak value | |
| 2. |
Inductance of coil___________? |
| A. | is unaffected by the supply frequency |
| B. | decreases with the increase in supply frequency |
| C. | increases with the increase in supply frequency |
| D. | becomes zero with the increase in supply frequency |
| Answer» D. becomes zero with the increase in supply frequency | |
| 3. |
Power factor of the following circuit will be zero__________? |
| A. | resistance |
| B. | inductance |
| C. | capacitance |
| D. | both B. and C. |
| Answer» E. | |
| 4. |
If two sinusoids of the same frequency but of different amplitudes and phase angles are subtracted, the resultant is____________? |
| A. | a sinusoid of the same frequency |
| B. | a sinusoid of half the original frequency |
| C. | a sinusoid of double the frequency |
| D. | not a sinusoid |
| Answer» B. a sinusoid of half the original frequency | |
| 5. |
For a frequency of 200 Hz, the time period will be__________? |
| A. | 0.05 s |
| B. | 0.005 s |
| C. | 0.0005 s |
| D. | 0.5 s |
| Answer» C. 0.0005 s | |
| 6. |
The power consumed in a circuit element will be least when the phase difference between the current and voltage is__________? |
| A. | 180″ |
| B. | 90° |
| C. | 60° |
| D. | 0° |
| Answer» C. 60° | |
| 7. |
The time constant of a series R-C circuit is given by____________? |
| A. | R/C |
| B. | RC2 |
| C. | RC |
| D. | R2C |
| Answer» D. R2C | |
| 8. |
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 |
| Answer» B. 50 jt | |
| 9. |
Pure inductive circuit____________? |
| A. | consumes some power on average |
| B. | does not take power at all from a line |
| C. | takes power from the line during some part of the cycle and then returns back to it during other part of the cycle |
| D. | none of the above |
| Answer» D. none of the above | |
| 10. |
In series resonant circuit, increasing inductance to its twice value and reducing capacitance to its half value__________? |
| A. | will change the maximum value of current at resonance |
| B. | will change the resonance frequency |
| C. | will change the impedance at resonance frequency |
| D. | will increase the selectivity of the circuit |
| Answer» E. | |
| 11. |
The period of a sine wave is _____ seconds. Its frequency is |
| A. | 20 Hz |
| B. | 30 Hz |
| C. | 40 Hz |
| D. | 50 Hz |
| Answer» E. | |
| 12. |
The peak value of a sine wave is 200 V. Its average value is___________? |
| A. | 127.4 V |
| B. | 141.4 V |
| C. | 282.8 V |
| D. | 200V |
| Answer» C. 282.8 V | |
| 13. |
Which of the following circuit component opposes the change in the circuit voltage ? |
| A. | Inductance |
| B. | Capacitance |
| C. | Conductance |
| D. | Resistance |
| Answer» C. Conductance | |
| 14. |
For the same peak value which of the following wave will ‘have the highest r.m.s. value? |
| A. | square wave |
| B. | half wave rectified sine wave |
| C. | triangular wave |
| D. | sine wave |
| Answer» B. half wave rectified sine wave | |
| 15. |
Time constant of an inductive circuit___________? |
| A. | increases with increase of inductance and decrease of resistance |
| B. | increases with the increase of inductance and the increase of resistance |
| C. | increases with decrease of inductance and decrease of resistance |
| D. | increases with decrease of inductance and increase of resistance |
| Answer» B. increases with the increase of inductance and the increase of resistance | |
| 16. |
In a highly capacitive circuit the__________? |
| A. | apparent power is equal to the actual power |
| B. | reactive power is more than the apparent power |
| C. | reactive power is more than the actual power |
| D. | actual power is more than its reactive power |
| Answer» D. actual power is more than its reactive power | |
| 17. |
Pure inductive circuit takes power from the A.C. line when_________? |
| A. | applied voltage decreases but current increases |
| B. | applied voltage increases but current decreases |
| C. | both applied voltage and current increase |
| D. | both applied voltage and current decrease |
| Answer» B. applied voltage increases but current decreases | |
| 18. |
In R-L-C series resonant circuit magnitude of resonance frequency can be changed by changing the value of__________? |
| A. | R only |
| B. | L only |
| C. | C only |
| D. | LorC |
| E. | R,LorC |
| Answer» E. R,LorC | |
| 19. |
Magnitude of current at resonance in R-L-C circuit________? |
| A. | depends upon the magnitude of R |
| B. | depends upon the magnitude of L |
| C. | depends upon the magnitude of C |
| D. | depends upon the magnitude of R, Land C |
| Answer» B. depends upon the magnitude of L | |
| 20. |
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 |
| Answer» B. capacitance is less and frequency of supply is more | |
| 21. |
Inductance of a coil Varies__________? |
| A. | directly as the cross-sectional area of magnetic core |
| B. | directly as square of number of turns |
| C. | directly as the permeability of the core |
| D. | inversely as the length of the iron path |
| E. | as A. to (d) |
| Answer» F. | |
| 22. |
Poor power factor________? |
| A. | reduces load handling capability of electrical system |
| B. | results in more power losses in the electrical system |
| C. | overloads alternators, transformers and distribution lines |
| D. | results in more voltage drop in the line |
| E. | results in all above |
| Answer» F. | |
| 23. |
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? |
| A. | 2.5 |
| B. | 5 |
| C. | 10 |
| D. | 15 |
| Answer» D. 15 | |
| 24. |
Power factor of the following circuit will be unity |
| A. | inductance |
| B. | capacitance |
| C. | resistance |
| D. | both A. and B. |
| Answer» D. both A. and B. | |
| 25. |
Two waves of the same frequency have opposite phase when the phase angle between them is_________? |
| A. | 360° |
| B. | 180° |
| C. | 90° |
| D. | 0° |
| Answer» C. 90° | |
| 26. |
Inductance affects the direct current flow__________? |
| A. | only at the time of turning off |
| B. | only at the time of turning on |
| C. | at the time of turning on and off |
| D. | at all the time of operation |
| Answer» D. at all the time of operation | |
| 27. |
The form factor is the ratio of_______? |
| A. | peak value to r.m.s. value |
| B. | r.m.s. value to average value |
| C. | average value to r.m.s. value |
| D. | none of the above |
| Answer» C. average value to r.m.s. value | |
| 28. |
The double energy transient occur in the____________? |
| A. | purely inductive circuit |
| B. | R-L circuit |
| C. | R-C circuit |
| D. | R-L-C circuit |
| Answer» E. | |
| 29. |
The period of a wave is___________? |
| A. | the same as frequency |
| B. | time required to complete one cycle |
| C. | expressed in amperes |
| D. | none of the above |
| Answer» C. expressed in amperes | |
| 30. |
The power consumed in a circuit element will be least when the phase difference between the current and voltage is________? |
| A. | 180″ |
| B. | 90° |
| C. | 60° |
| D. | 0° |
| Answer» C. 60° | |
| 31. |
The r.m.s. value and mean value is the same in the case of___________? |
| A. | triangular wave |
| B. | sine wave |
| C. | square wave |
| D. | half wave rectified sine wave |
| Answer» D. half wave rectified sine wave | |
| 32. |
Power factor of an electrical circuit is equal to____________? |
| A. | R/Z |
| B. | cosine of phase angle difference be-tween current and voltage |
| C. | kW/kVA |
| D. | ratio of useful current to total cur¬rent Iw/I |
| E. | all of these |
| Answer» F. | |
| 33. |
In a pure inductive circuit___________? |
| A. | the current is in phase with the voltage |
| B. | the current lags behind the voltage by 90° |
| C. | the current leads the voltage by 90° |
| D. | the current can lead or lag by 90° |
| Answer» C. the current leads the voltage by 90° | |
| 34. |
The r.m.s. value of a sinusoidal A.C. current is equal to its value at an angle of_______degrees? |
| A. | 90 |
| B. | 60 |
| C. | 45 |
| D. | 30 |
| Answer» D. 30 | |
| 35. |
Capacitors for power factor correction are rated in_________? |
| A. | kW |
| B. | kVA |
| C. | kV |
| D. | kVAR |
| Answer» E. | |
| 36. |
For the same peak value, which of the following wave has the least mean value ? |
| A. | half wave rectified sine wave |
| B. | triangular wave |
| C. | sine wave |
| D. | square wave |
| Answer» B. triangular wave | |
| 37. |
Power factor of the system is kept high__________? |
| A. | to reduce line losses |
| B. | to maximise the utilization of the capacities of generators, lines and transformers |
| C. | to reduce voltage regulation of the line |
| D. | due to all above reasons |
| Answer» E. | |
| 38. |
In a loss-free R-L-C circuit the transient current is__________? |
| A. | oscillating |
| B. | square wave |
| C. | sinusoidal |
| D. | non-oscillating |
| Answer» D. non-oscillating | |
| 39. |
For a sine wave with peak value Imax the r.m.s. value is_______? |
| A. | 0.5 Imax |
| B. | 0.707 |
| C. | 0.9 |
| D. | 1.414 Lmax |
| Answer» C. 0.9 | |
| 40. |
Form Factor is the ratio of__________? |
| A. | average value/r.m.s. value |
| B. | average value/peak value |
| C. | r.m.s. value/average value |
| D. | r.m.s. value/peak value |
| Answer» D. r.m.s. value/peak value | |
| 41. |
Form factor for a sine wave is________? |
| A. | 1.414 |
| B. | 0.707 |
| C. | 1.11 |
| D. | 0.637 |
| Answer» D. 0.637 | |
| 42. |
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 |
| Answer» C. the less heat than produced by A.C. flowing through the same circuit | |
| 43. |
For a sine wave with peak value Emax _______ 8.30. the average value is? |
| A. | 0.636 Emax |
| B. | 0.707 Emax |
| C. | 0.434 EWc |
| D. | lAUEmax |
| Answer» B. 0.707 Emax | |
| 44. |
The square waveform of current has following relation between r.m.s. value and average value? |
| A. | r.m.s. value is equal to average value |
| B. | r.m.s. value of current is greater than average value |
| C. | r.m.s. value of current is less than average value |
| D. | none of the above |
| Answer» B. r.m.s. value of current is greater than average value | |
| 45. |
The time constant of the capacitance circuit is defined as the time during which voltage________? |
| A. | falls to 36.8% of its final steady value |
| B. | rises to 38.6% of its final steady value |
| C. | rises to 63.2% of its final steady value |
| D. | none of the above |
| Answer» D. none of the above | |
| 46. |
In a circuit containing R, L and C, power loss can take place in____________? |
| A. | C only |
| B. | L only |
| C. | R only |
| D. | all above |
| Answer» D. all above | |
| 47. |
The transient currents are associated with the____________? |
| A. | changes in the stored energy in the inductors and capacitors |
| B. | impedance of the circuit |
| C. | applied voltage to the circuit |
| D. | resistance of the circuit |
| Answer» B. impedance of the circuit | |
| 48. |
All the rules and laws of D.C. circuit also apply to A.C. circuit containing_____________? |
| A. | capacitance only |
| B. | inductance only |
| C. | resistance only |
| D. | all above |
| Answer» D. all above | |
| 49. |
In a pure resistive circuit__________? |
| A. | current lags behind the voltage by 90° |
| B. | current leads the voltage by 90° |
| C. | current can lead or lag the voltage by 90° |
| D. | current is in phase with the voltage |
| Answer» E. | |
| 50. |
The phase difference between voltage and current wave through a circuit element is given as 30°. The essential condition is that |
| A. | both waves must have same frequency |
| B. | both waves must have identical peak values |
| C. | both waves must have zero value at the same time |
| D. | none of the above |
| Answer» B. both waves must have identical peak values | |