Electrical Circuits MCQ Solved Paper for RRB NTPC

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

2. What is the conductance of a circuit having three 10 resistors in parallel?
A. 0.3 S
B. 3.33 S
C. 0.33 S
D. 30 S
Answer : A

3. 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

4. Thevenin�s theorem is what form of an equivalent circuit?
A. Current
B. Voltage
C. Both current and voltage
D. Neither current nor voltage
Answer : B

5. 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

6. 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

7. An inductive load always has a ___ power factor
A. Leading
B. Lagging
C. Zero
D. Unity
Answer : B

8. The internal resistance of an ideal current source is
A. Infinite
B. Zero
C. Equal to the load resistance
D. To be determined
Answer : A

9. Which is considered as the effect of a dielectric material?
A. Increasing capacitance
B. Decreasing capacitance
C. Reducing the working voltage
D. Increasing the distance between the plates
Answer : A

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

11. What theorem is usually used in the analysis of transistor circuit?
A. Superposition theorem
B. Millman�s theorem
C. Thevenin�s theorem
D. Norton�s theorem
Answer : D

12. In an ac wavea 30 degrees of phase is ___ of a cycle.
A. ½
B.
C.
D.
Answer : B

13. 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

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

15. In a complex resistance-reactance planea XLis represented
A. By an axis opposite the R axis
B. By an axis perpendicular to the XC axis
C. By an axis opposite the XCaxis
D. By an axis parallel to the R axis
Answer : C

16. 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

17. A three-by-threea series-parallel matrix of resistorsa all having the same ohmic valuea would have a net resistance of
A. One-third the value of a single resistor
B. Three times the value of a single resistor
C. The same value as a single resistor
D. Nine times the value of a single resistor
Answer : C

18. The ratio between the active power and the apparent power of a load in an ac circuit is called
A. Quality factor
B. Power factor
C. Power ratio
D. Power reactive
Answer : B

19. The Q-factor of a parallel resonant circuit is also known as
A. Voltage magnification factor
B. Current magnification factor
C. Gain magnification factor
D. Resonance magnification factor
Answer : B

20. 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

21. 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

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

23. The internal resistance of an ideal voltage source is
A. Infinite
B. Equal to the load resistance
C. Zero
D. To be determined
Answer : C

24. What is the complex impedance of a circuit with an absolute resistance of 300 ?
A. 0 + j 300
B. 300 + j 90
C. 0 ± j 300
D. 300 +j 0
Answer : D

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

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

27. As applied to a series RLCcircuita bandwidth means
A. The frequency range for maximum power transfer
B. The difference between the highest and lowest frequencies of the oscillator
C. The separation of the half-power points
D. The frequency at which XL= XC
Answer : C

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

29. What determines the magnitude of electric current?
A. The rate at which electrons are produced
B. The type of material used
C. The current carrying capacity of the circuit
D. The rate at which electrons pass a given point
Answer : D

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

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

32. The reciprocal of a complex number is
A. A complex number
B. A real number
C. An imaginary number
D. A whole number
Answer : A

33. In calculating maximum instantaneous power ___ voltage or current is used.
A. Peak
B. Average
C. Rms
D. Instantaneous
Answer : A

34. 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

35. The superposition theorem is used when the circuit contains
A. Reactive elements
B. Active elements
C. Number of voltage sources
D. Single voltage source
Answer : C

36. The voltage cannot be exactly in phase with the current in a circuit that contains
A. Only capacitance
B. Only resistance
C. Inductance and capacitance
D. Inductancea capacitance and resistance
Answer : A

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

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

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

40. 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

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. What is the temperature coefficient of the resistance Eureka?
A. Infinity
B. Negative
C. Almost zero
D. Positive
Answer : C

43. 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

44. 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

45. 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

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

47. Another term for superconductor.
A. Generic conductor
B. Ultraconductor
C. Cryotron
D. Cryogenic conductor
Answer : D

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

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

50. 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