Electrical Circuits MCQ Solved Paper for RRB Group D

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

2. For a parallel ACcircuita ___ is used as a reference phasor.
A. Voltage
B. Power
C. Current
D. Resistance
Answer : A

3. 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

4. Barium-strontium titanite dielectric material is also called
A. Ceramic
B. Polyster
C. Electrolytic
D. Bakelite
Answer : A

5. 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

6. Electric energy refers to
A. Volt divided by coulomb
B. Voltampere
C. Volt-coulomb
D. Watt divided by time
Answer : C

7. In the 5-band method of capacitor color codinga the first band indicates
A. Temperature coefficient
B. Tolerance
C. 1stdigit
D. Capacitance value
Answer : A

8. The charging of a capacitor through a resistance follows what law?
A. Linear law
B. Hyperbolic law
C. Inverse-square law
D. Exponential law
Answer : D

9. The power factor of a circuit is equal to
A. RZ
B. XC/Z
C. XL/Z
D. R/Z
Answer : D

10. At parallel resonancea the currents flowing through L and C are
A. Infinite
B. Zero
C. Unequal
D. Equal
Answer : D

11. A term used to express the amount of electrical energy stored in electrostatic field.
A. Joules
B. Coulombs
C. Watts
D. Electron-volt
Answer : A

12. 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

13. 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

14. 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

15. 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

16. The ratio between the reactive power and the apparent power of an ac load is called
A. Quality factor
B. Power factor
C. Power ratio
D. Reactive power
Answer : D

17. 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

18. The distance between the capacitor plates increases two timesa then its capacitance
A. Increases two times
B. Increases four times
C. Decreases two times
D. Decreases four times
Answer : C

19. Leakage resistance in a capacitor results into
A. Internal heating
B. Internal bleeding
C. Shorter useful life
D. Short-circuiting
Answer : A

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

21. In dividing or multiplying phasor quantitiesa ___ form is used.
A. Polar
B. Rectangular
C. Trigonometric
D. Exponential
Answer : A

22. The maximum power transfer theorem is used in
A. Power system
B. Electronic system
C. Refrigeration
D. Air conditioning
Answer : B

23. An ac series circuit is composed of a resistance of 20 a inductive reactance of 40 a and a capacitive reactance of 15 . If a current of 1 ampere is flowinga what is the applied voltage
A. 320 V
B. 32 V
C. 220 V
D. 22 V
Answer : B

24. When the movable plates of a gang capacitor completely overlap the fixed platesa the capacitance of the capacitor is
A. Halfway between maximum and minimum
B. Maximum
C. Minimum
D. Zero
Answer : B

25. What maximum voltage can be applied across the capacitor of time?
A. Working voltage
B. Surge voltage
C. Stray voltage
D. Peak voltage
Answer : B

26. Which of the following does not refer to electrical energy?
A. Volt-ampere
B. Joule
C. Watt-second
D. Volt-coulomb
Answer : A

27. It is impossible to change the voltage across a capacitor instantlya as this would produce ___ current.
A. Infinite
B. Zero
C. Low
D. High
Answer : A

28. 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

29. 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

30. Tungsten filament of bulbs has a hot resistance higher than its cold resistance due to its temperature coefficient which is
A. Positive
B. Negative
C. Zero
D. Infinite
Answer : A

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

32. What is the specific resistance of a pure germanium?
A. 55 -cm
B. 55 -m
C. 55 -mm
D. 55 k -m
Answer : A

33. 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

34. Which of the following capacitors are used only in dc circuits?
A. Mica
B. Ceramic
C. Mylar
D. Electrolytic
Answer : D

35. 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

36. 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

37. 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

38. The unit of elastance is
A. Farad
B. Daraf
C. Siemen
D. Henry
Answer : B

39. The ohmic value of a resistor with negative temperature coefficient
A. Increases with increasing temperature
B. Increase with decreasing temperature
C. Stays unchanged with temperature change
D. Stays unaffected even with increasing temperature
Answer : B

40. What does a capacitor store?
A. Voltage
B. Charge
C. Current
D. Power
Answer : B

41. If an emf in circuit A produces a current in circuit Ba then the same emf in circuit Bproduces the same current in circuit ? this theorem is known as
A. Maximum power transfer theorem
B. Millman�s theorem
C. Reciprocity theorem
D. Norton�s theorem
Answer : C

42. If resonant frequency is 10 kHz and quality factor is 50a then
A. Bandwidth is 200 Hz
B. XL= is 50a000
C. R is 50
D. XC= is 50a000
Answer : A

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

44. What is the resonant frequency of a circuit when L of 25 microhenrys and C of 10 picofarads are in parallel?
A. 10.1 kHz
B. 10.1 MHz
C. 101 MHz
D. 101 kHz
Answer : B

45. A tank circuit is a
A. Parallel LC circuit
B. Series LCcircuit
C. A resonant circuit
D. A non-resonant circuit
Answer : A

46. 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

47. What is the most common non-sinusoidal waveform?
A. Square wave
B. Triangular wave
C. Trapezoidal wave
D. Sawtooth wave
Answer : A

48. What is the reciprocal of quality factor?
A. Power factor
B. Reactive factor
C. Dissipation factor
D. 1/Q factor
Answer : C

49. A capacitor of 0.5 F charged to 220 V is connected across an uncharged 0.5 F capacitor. What is the voltage across each capacitor?
A. 220 V
B. 150 V
C. 110 V
D. 22 V
Answer : C

50. Effects of capacitance
A. It opposes any change in the amount of voltage
B. Voltage is lagged behind the current by a quarter cycle
C. Electric energy is stored in the capacitor in the form of electrostatic field
D. All of the above
Answer : D