1000+ Electrical Circuits Multiple Choice Question Answer [Solved]

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

2. In a circuita a passive element is one which
A. Supplies energy
B. Receives energy
C. Both supplies and receives energy
D. Attenuates signal
Answer : B

3. 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

4. A capacitor opposes change in
A. Voltage
B. Current
C. Voltage and current
D. Neither voltage nor current
Answer : A

5. If two complex conjugates are addeda ___ components results.
A. In-phase
B. Quadrature
C. Complex
D. Outof-phase
Answer : A

6. Two capacitors of capacitance 9 F and 18 F in series will have a total capacitance of
A. 27 F
B. 162 F
C. 6 F
D. 180 F
Answer : C

7. What can be used to estimate resonant frequency and to find reactance at any frequency for any value of capacitor or inductor?
A. Smith chart
B. Reactance chart
C. Impedance chart
D. Resonance chart
Answer : B

8. The open-circuit voltage at the terminal of load RL is 60V. Under the condition of maximum power transfera the load voltage will be
A. 60 V
B. 15 V
C. 20 V
D. 30 V
Answer : D

9. In adding or subtracting phasor quantitiesa ___ form is the most convenient.
A. Polar
B. Rectangular
C. Trigonometric
D. Exponential
Answer : B

10. A real current source has
A. Infinite internal resistance
B. Zero internal resistance
C. Large internal resistance
D. Small internal resistance
Answer : C

11. The mutual inductance between two coils is ___ the reluctance of magnetic path.
A. Directly proportional to
B. Inversely proportional to
C. Independent to
D. Equal to
Answer : B

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

13. When capacitors are connected in seriesa the total capacitance is
A. Smaller than the smallest capacitor
B. Smaller than the largest capacitor
C. Greater than any of the capacitor
D. Greater than the largest capacitor
Answer : A

14. Which of the following does not generally affect the value of a capacitor?
A. The dielectric material used
B. The surface area of the plates
C. The thickness of the dielectric
D. The voltage applied to the plate
Answer : D

15. In an ac circuit with inductive reactance ?, the
A. Phase angle of the circuit is always 45�
B. Voltage across the inductance must be 90� out o f-phase witht he applied voltage
C. Current through the inductance lags its induced voltage by 90�
D. Current through the inductance and voltage across it are180� outof-phase
Answer : C

16. Liquids that are good conductors because of ionization are called
A. Electrolytic
B. Bases
C. Acid
D. Electrolytes
Answer : D

17. A linear circuit is one whose parameters
A. Change with change in voltage
B. Change with change in current
C. Do not change with voltage and current
D. Change with change in voltage and current
Answer : C

18. An electric circuit contains
A. Passive elements
B. Active elements
C. Both active and passive elements
D. Reactive elements
Answer : C

19. 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

20. Why are inductance and capacitance not relevant in a dc circuit?
A. Because it is a simple circuit
B. Because dc circuits require only resistance as load
C. Because they do not exist in a dc circuit
D. Because frequency of dc is zero
Answer : D

21. Property of an electric circuit that dissipates electric energy
A. Reactance
B. Impedance
C. Resistance
D. Conductance
Answer : C

22. The reactance curve is a plot of frequency versus _____ for a series RLCcircuit
A. Current
B. Voltage
C. Gain
D. Impedance
Answer : A

23. At what frequency will the current in a series RLCcircuit reach its maximum value for an applied voltage of 15 V with R = 500 a L = 100 H and C= 0.001 F?
A. 503 kHz
B. 403 kHz
C. 603 kHz
D. 303 kHz
Answer : A

24. 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

25. Which of the following conditions is not true for a series RLCcircuit at resonance?
A. Z = jXL
B. XL= XC
C. The power factor is one
D. The magnitude of Z is
Answer : A

26. In a series RLCcircuit
A. Increasing the frequency decreases the resistance
B. Increasing the frequency increases the resistance
C. Both XLand XCchange as frequency changes
D. Impedance will always decrease
Answer : C

27. A law which states that when a constant electromotive force is applied to a circuit consisting of a resistor and capacitor connected in seriesa the time taken for the potential on the plates of the capacitor to rise to any given fraction of its final value depends only on the product of capacitance and resistance.
A. Child�s law
B. CR law
C. Coulomb�s law
D. Debye T3 law
Answer : B

28. In an ac circuita the power dissipated as heat depends on
A. Impedance
B. Capacitive reactance
C. Resistance
D. Inductive reactance
Answer : C

29. 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

30. When the net reactance in a series coil-capacitor circuit is zero at frequency fa the nature of its reactance of frequency 2f is
A. Inductive
B. Capacitive
C. Resistive
D. Infinite
Answer : A

31. With double the number of turns by the same length and areaa the inductance is
A. The same
B. Doubled
C. Quartered
D. Quadrupled
Answer : D

32. Of the equivalent combination of unitsa which one is not equal to watt?
A. 2/V
B. AV
C. A2
D. J/s
Answer : A

33. 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

34. A series RLCcircuit consists of a 10 resistor in series with L = 10 Ha and C= 100 F. Determine a new value of Ia for which the resonant frequency is one ±half the original value.
A. 40 H
B. 40 mH
C. 40 pH
D. 40 nH
Answer : A

35. In Norton�s theorema the short circuit current is obtained by
A. Opening the load terminals
B. Shorting the load terminals
C. Opening the voltage source
D. Shorting the voltage source
Answer : B

36. A wire of one kilometre length has a resistance of 20 . If the length is halveda then the new resistance is ___ the original resistance.
A. Half
B. Twice
C. One-fourth
D. Three times
Answer : A

37. Parallel resonant circuit is sometimes called as
A. Acceptor circuit
B. Rejector circuit
C. Inductive circuit
D. Capacitive circuit
Answer : B

38. And ideal current source has an internal conductance of _____ siem
A. Infinite
B. One
C. Zero
D. One million
Answer : C

39. The usual load of a dc circuit is a/an
A. Resistor
B. Capacitor
C. Inductor
D. Both inductor and capacitor
Answer : A

40. An inductive circuit of resistance 16.5 and inductance of 0.14 H takes a current of 25 ?. if the frequency is 50 Hza find the supply voltage.
A. 1501 V
B. 1174V
C. 1877V
D. 991 V
Answer : B

41. Electron flow assumes charges flow from
A. Negative to positive
B. Negative to negative
C. Positive to negative
D. Positive to positive
Answer : A

42. For greater accuracya the value of phase angle should be determined from
A. Cos
B. Tan
C. Sin
D. Sec
Answer : B

43. The current is ____ times the maximum current at half-power points of a resonance curve.
A.
B.
C.
D.
Answer : A

44. For a series circuita the higher the quality factor
A. The greater the bandwidth
B. The narrower the passband
C. The broader the resonance curve
D. The wider the passband
Answer : B

45. Permeability is otherwise known as
A. Magnetic conductivity
B. Magnetic susceptibility
C. Electric conductivity
D. Electric susceptibility
Answer : A

46. A factor that states how much the resistance changes for a change in temperature?
A. Resistivity
B. Specific resistance
C. Coefficient of temperature change
D. Temperature coefficient of resistance
Answer : D

47. The arc across a switch when it open an RL circuit is a result of the
A. Large self-induced voltage across L
B. Long time constant
C. Low resistance of the open switch
D. Surge of resistance
Answer : A

48. The average value of a triangular or sawtooth wave is _____ times its peak value.
A.
B.
C.
D.
Answer : B

49. Which of the statements below is not true?
A. Current source is an active element
B. Resistor is a linear element
C. Voltage source is a passive element
D. Diode is a non-linear element
Answer : C

50. What is the reciprocal of capacitance?
A. Reluctance
B. Susceptance
C. Elastance
D. Conductance
Answer : C