1000+ Electrical Circuits MCQ for LIC AAO [Solved]

1. An impedance given by 90 -45� is a/an ___ impedance.
A. Inductive
B. Conductive
C. Resistive
D. Capacitive
Answer : D

2. When resistance are connected in parallela the total resistance is
A. Less than the smallest resistance in the connection
B. Greater than the smallest resistance in the connection
C. Between the smallest and greatest resistance in the connection
D. Increasing and decreasing depending upon the supply voltage
Answer : A

3. Which of the following capacitors is suitable for dc filter circuits?
A. Mica
B. Ceramic
C. Paper
D. Electrolytic
Answer : D

4. According to Gauss theorema flux can be equated to
A. Charge
B. Field intensity
C. Current
D. Voltage
Answer : A

5. The curve between current and frequency is termed as
A. Voltage curve
B. Gain curve
C. Power curve
D. Resonance curve
Answer : D

6. In a series RLCcircuit
A. The current lags VLby 90�
B. The current leads VLby 90�
C. XL leads Xcby 90�
D. Z = jXL at resonance
Answer : A

7. For maximum power transfera what is the relation between load resistance RL and internal resistance R of the voltage source?
A. RL= 2 r
B. RL= 1.5 r
C. RL= r
D. RL= 3 r
Answer : C

8. A 5 F capacitor charge to 5V has a stored charge equal to
A. 1 c
B. 5 c
C. 25 C
D. 200 c
Answer : C

9. The reason why alternating current can induce voltage is
A. It has high peak value
B. It has a stronger magnetic field than direct current
C. It has a constant magnetic field
D. It has a varying magnetic field
Answer : D

10. Delta to wye or wye to delta transformation technique is applied to a ___ network.
A. One-terminal
B. Two-terminal
C. Three-terminal
D. Complex
Answer : C

11. What value of R is needed with a 0.05 F Cfor an RCtime constant of 0.02 s?
A.
B. 400 M
C. 400 G
D. 400 k
Answer : D

12. A neon glow lamp used as a night light ionizes at approximately
A. 70 V
B. 80 V
C. 90 V
D. 100 V
Answer : A

13. Which of the following is a way of decreasing mutual inductance?
A. Moving the coils closer
B. Moving the coils apart
C. Decreasing the number of turns of either coil
D. Increasing the number of turns of either coil
Answer : B

14. If the output resistance of a voltage source is 4 a it internal resistance should be
A.
B.
C.
D. Infinite
Answer : A

15. Which statement is true?
A. A series resonant circuit is of high impedance
B. A parallel resonant circuit is of low impedance
C. A series resonant circuit is inductive if it operates at a frequency higher than the resonant frequency
D. A parallel resonant circuit is inductive if it operates at a frequency higher than the resonant frequency
Answer : C

16. What dielectric is generally employed by a variable capacitor?
A. Mica
B. Air
C. Electrolyte
D. Ceramic
Answer : B

17. What is the purpose of a load in an electric circuit?
A. To increase the circuit current
B. To decrease the circuit current
C. To utilize electrical energy
D. To make the circuit complete
Answer : C

18. A capacitor is basically constructed of
A. Two conductors separated by a dielectric
B. Two dielectric separated by a conductor
C. Conductors and dielectric
D. Conductors and semiconductors
Answer : A

19. The temperature coefficient of resistance of electrolytes is
A. Negative
B. Positive
C. Zero
D. Infinite
Answer : A

20. What theorem is generally used in the analysis of vacuum tubes?
A. Superposition theorem
B. Millman�s theorem
C. Thevenin�s theorem
D. Norton�s theorem
Answer : C

21. In a series circuit with unequal resistances the
A. Highest R has the highest V
B. Lowest R has the highest V
C. Lowest R has the highest I
D. Highest R has the highest I
Answer : A

22. Which of the following has a positive temperature coefficient?
A. Mica
B. Manganin
C. Silicon
D. Carbon
Answer : B

23. What capacitance exists not through design but simply because two conducting surfaces are relatively close to each other?
A. Surge
B. Stray
C. Natural
D. Normal
Answer : B

24. What is the half-power bandwidth of a parallel resonant circuit which has a resonant frequency of 3.6 MHz and Q of 218?
A. 1.65 kHz
B. 16.5 MHz
C. 16.5 kHz
D. 165 kHz
Answer : C

25. In a rectangular wavea the peak factor is
A.
B.
C.
D.
Answer : D

26. What is the rms value of a square wave?
A. Equals its peak value
B. Equals its peak-to-peak value
C. Peak divided by square root of two
D. Peak divided by pi
Answer : A

27. The wavelength of an alternating waveform depends upon the ___ of the variation.
A. Period
B. Number
C. Frequency
D. Amplitude
Answer : C

28. When two in-phase sine waves that have identical frequency and amplitude are added togethera then the result is a sine wave with ___ the amplitude of either.
A. Half
B. Twice
C. Four times
D. One-fourth
Answer : B

29. What refers to the lowest voltage across any insulator that can cause current flow?
A. Conduction voltage
B. Critical voltage
C. Breakdown voltage
D. Voltage capacity
Answer : C

30. A capacitance of 0.05 F equals
A. 0.05 x 106F
B. 0.05 x 10-6F
C. 0.05 x 10-12F
D. 0.05 x 1012F
Answer : B

31. A capacitor consists of two
A. Conductors only
B. Dielectric only
C. Conductors separated by a dielectric
D. Dielectric separated by a conductor
Answer : C

32. Which of the following is a common material used in wire-wound resistors?
A. Manganin
B. Carbon
C. Bronze
D. German silver wire
Answer : A

33. A 0.09 microfarad capacitor is charged to 220 volts. How long in milliseconds will it discharged resistor has a resistance of 20a000 ohms?
A.
B.
C.
D.
Answer : C

34. Norton�s theorem is ____ Thevenin�s theorem.
A. The same as
B. The converse of
C. Older that
D. More accurate than
Answer : B

35. Points to be considered in choosing a capacitor
A. Working voltage
B. Type of dielectric
C. Capacitance
D. All of the above
Answer : D

36. The charge in the capacitor is stored at the
A. Terminals
B. Plates
C. Dielectric
D. Air
Answer : B

37. What is the resonant frequency of a circuit when L of 3 microhenrys and C of 40 picofarads are in series?
A. 14.5 kHz
B. 145 MHz
C. 14.5 MHz
D. 145 kHz
Answer : C

38. When the power factor of a circuit is zeroa
A. Power absorbed is maximum
B. Power absorbed is minimum
C. Power absorbed is zero
D. The impedance is minimum
Answer : C

39. An open inductor has
A. Zero resistance and infinite inductance
B. Infinite resistance and zero inductance
C. Infinite resistance and infinite inductance
D. Zero resistance and zero inductance
Answer : B

40. An intermittent and non-symmetrical alternating current like that obtained from the secondary winding of an induction coil
A. Faradic current
B. Transient ac current
C. Inductive current
D. Capacitive current
Answer : A

41. For a linear circuita ___ voltage or current is used to calculate average power.
A. Rms
B. Peak
C. Average
D. Instantaneous
Answer : A

42. An inductor carries 2 A dc. If its inductance is 100 Ha then what is its inductive reactance?
A. Zero
B. 1.3 k
C.
D.
Answer : A

43. Which of the following is not a factor affecting dielectric strength?
A. Mass
B. Moisture content
C. Temperature
D. Thickness
Answer : A

44. Which factor does not affect resistance?
A. Length
B. Resistivity
C. Cross-sectional area
D. Mass
Answer : D

45. The resistance of an insulator ___ when its temperature is increased.
A. Decreases
B. Remains the same
C. Increases
D. Varies
Answer : A

46. A switch designed to have low capacitance between its terminal when open.
A. LOCAP switch
B. AntiLOCAP switch
C. Anticapacitance switch
D. Capacitance switch
Answer : C

47. When two complex conjugates are subtracteda the result is a
A. Quadrature component only
B. Complex component
C. In-phase component
D. Real component
Answer : A

48. If the inductance is decreaseda the impedance of the circuit containing a resistor a capacitor and an inductor connected in series to an ac source
A. Decreases
B. Increases
C. Decreases or increases
D. Decreasesa increases or remains the same
Answer : C

49. What is the peak factor for alternating current or voltage varying sinusiodally?
A.
B.
C.
D.
Answer : A

50. The reason why electrical appliances are connected in parallel.
A. It is a simple circuit
B. This makes the operation of appliances independent with each other
C. This results in reduced power consumption
D. All of the above
Answer : B