1000+ Electrical Circuits MCQ for CAT [Solved]

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

2. What is considered as the most important value of a sine wave?
A. Effective value
B. Peak value
C. Average value
D. Instantaneous value
Answer : A

3. What is the time constant for L of 240 mH in series with R of 20 ?
A. 12 ms
B. 4.8 s
C. 83.3 s
D. 12 s
Answer : A

4. The Q-factor of a series resonant circuit is also known as
A. Current magnification factor
B. Voltage magnification factor
C. Load factor
D. Leakage factor
Answer : B

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

6. In a parallel bank with unequal branch resistances
A. The highest R has the highest I
B. The lowest R has the highest V
C. The lowest R has the highest V
D. The highest R has the highest V
Answer : B

7. 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

8. For a series ACcircuita ___ is not used as a reference phasor.
A. Voltage
B. Impedance
C. Current
D. Conductance
Answer : A

9. A coil of inductance L has an inductive reactance of XLin an ac circuit in which the effective current is I. The coil is made from a superconducting material. The rate at which power is dissipated in the coil is
A.
B. I2XL
C. IXL
D. IXL2
Answer : A

10. 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

11. 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

12. Voltage resonance means
A. Series resonance
B. Parallel resonance
C. Current magnification
D. Gain magnification
Answer : A

13. A capacitive load always has a ______ power facto
A. Leading
B. Lagging
C. Zero
D. Unity
Answer : A

14. Loop currents should be assumed to flow in which direction
A. Straight
B. Clockwise
C. Counter-clockwise
D. Either B or C arbitrarily selected
Answer : D

15. The symbol Q refers to
A. Resonance quotient
B. Quality factor
C. Power quotient
D. Qualification test
Answer : B

16. Series resonance occurs when
A. XL= XC
B. XL= R
C. Z = R
D. Both A and C
Answer : D

17. Rationalizing the denominator of a complex number means
A. Eliminating the j component in the denominator
B. Adding j component in the denominator
C. Eliminating the j component in the numerator
D. Adding j component in the numerator
Answer : A

18. In an ac circuit with a resistive branch and an inductive branch in parallela the
A. Voltage across the inductance leads the voltage across the resistance by 90°
B. Resistive branch current is 90° out of phase with the inductive branch current
C. Resistive and inductive branch currents have the same phase
D. Resistive and inductive branch currents are 180° outof-phase
Answer : B

19. 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

20. A capacitor is used to
A. Block dc current
B. Pass dc current
C. Open voltage source
D. Short the voltage source
Answer : A

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

22. If the capacitance of mica capacitor is 5 times the capacitcitora then the relative permittivity of mica is
A.
B.
C.
D.
Answer : B

23. How many coulombs are delivered by a storage battery in 25 hours if it is supplying current at the rate of 3 A?
A. 2.592 x 105C
B. 2.592 x 103 C
C. 2.592 x 108 C
D. 2.592 x 1012 C
Answer : A

24. The voltage lags the current by cycle in a
A. Purely resistive circuit
B. Purely inductive circuit
C. Purely capacitive circuit
D. Circuit containing resistancea capacitance and inductance
Answer : C

25. 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

26. VL= VCin a series RLCcircuit when
A. The value of the impedance is minimum
B. The power factor is zero
C. The current leads the total voltage by 90�
D. The total voltage is zero
Answer : A

27. Which of the following materials has the lowest dielectric strength?
A. Glass
B. Paper
C. Mica
D. Teflon
Answer : B

28. An inductance of 1 mH is
A. 0.001 H
B. 0.01 H
C. 0.0001 H
D. 0.10 H
Answer : A

29. Which of the following is the most popular waveform?
A. Sinusoidal
B. Square wave
C. Triangular
D. Sawtooth
Answer : A

30. In a rectangular wavea the form factor is
A.
B.
C.
D.
Answer : C

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

32. The Q-factor of a parallel resonant circuit is also known as
A. Current magnification factor
B. Voltage magnification factor
C. Load factor
D. Leakage factor
Answer : A

33. The ratio of W/VA in an ac circuit means
A. Power factor
B. Reactive factor
C. Quality factor
D. Load factor
Answer : A

34. 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

35. What is the value of a carbon composition resistor with the following color code: Browna whitea orangea red
A. 190 ; 10 %
B. 19 k ; 2 %
C. 19 k ; 20 %
D. 1.9 k ; 2 %
Answer : B

36. What fusion of elements is without chemical action between them?
A. Mixture
B. Compound
C. Alloy
D. Ionization
Answer : C

37. Which of the following is also known as antiresonant circuit?
A. Parallel resonant circuit
B. Series resonant circuit
C. Tuned circuit
D. Tank circuit
Answer : A

38. 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

39. 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

40. What is a closed path made of several branches of the network called?
A. Junction
B. Node
C. Terminal
D. Loop
Answer : D

41. Form its definitiona the unit of electric fielda is the N/C and equivalent unit of is the
A. V(m)2
B. V(m)
C. V/m2
D. V/m
Answer : D

42. 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

43. For multi-plate capacitora capacitance is proportional to
A. Number of plates less one(n ± 1)
B. Number of plates plus one(n + 1)
C. Number of plates less two(n - 2)
D. Number of plates (n)
Answer : A

44. A capacitor requires 12 C of charge to raise its potential of 3 V. What is the capacitance of the capacitor?
A. 36 F
B. 15 F
C. 0.25 F
D. 4 F
Answer : D

45. What is the most convenient way of achieving large capacitance?
A. By using multiplate construction
B. By using air as dielectric
C. By decreasing distance between plates
D. By using dielectric of low permittivity
Answer : A

46. What is the total resistance of a two equal valued resistors in series?
A. The difference of both
B. The product of both
C. Twice as one
D. The sum of their reciprocals
Answer : C

47. A circuit whose parameters change with voltage or current.
A. Non-linear circuit
B. Linear circuit
C. Complex circuit
D. Passive circuit
Answer : A

48. The farad is not equivalent to which of the following combination of units
A. CV2
B. C2/J
C. C/V
D. J/V2
Answer : A

49. What is the other name of relative permittivity?
A. Dielectric strength
B. Potential gradient
C. Breakdown voltage
D. Specific inductance capacity
Answer : D

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