XAT - Electrical Circuits 1000+ MCQ [Solved] PDF Download

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

2. The ratio of maximum value to the effective value of an alternating quantity is called
A. Form factor
B. Peak factor
C. Dynamic factor
D. Leakage factor
Answer : B

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

4. Another term of the quality factor of the resonant circuit.
A. Figure of merit
B. Figure of demerit
C. Noise factor
D. Noise figure
Answer : A

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

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. 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

8. 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

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. What is the form factor of a triangular wave?
A.
B.
C.
D.
Answer : A

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

12. 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

13. 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

14. 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

15. What is expected when two 20 k a 1 watt resistor in parallel are use instead of one 10 k a 1 watt?
A. Provides higher current
B. Provides less power
C. Provides more power
D. Provides wider tolerance
Answer : C

16. 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

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

18. A gang capacitor is a variable capacitor in which capacitance is varied by changing the
A. Dielectric
B. Number of plates
C. Plate area
D. Distance between plates
Answer : C

19. 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

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

21. If three 9 mH inductors are connected in parallel without mutual inductance then the total i nductance is
A. 3 mH
B. 9 mH
C. 27mH
D. 18 mH
Answer : A

22. When two pure sine waves of the same frequency and the same amplitude which are exactly 180� outof-phase are added togethera the result is
A. A wave with twice the amplitude
B. A wave with half the amplitude
C. Zero signal
D. A wave with twice the frequency
Answer : C

23. In liquids and gasesa ionization current results from a flow of
A. Positive or negative ions
B. Free electrons
C. Ions that are lighter in weight than electrons
D. Protons
Answer : B

24. What is a rotating vector whose projection can represent either current or voltage in an ac circuit?
A. Polar diagram
B. Scalar quantity
C. Velocity
D. Phasor
Answer : D

25. What determines the direction of induced emf in a conductor or coil?
A. Cork screw rule
B. Fleming�s left hand rule
C. Ampere�s circuital law
D. Fleming�s right hand rule
Answer : D

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

27. The admittance of a parallel RLC circuit is found to be the ___ sum of conductance and susceptances.
A. Algebraic
B. Arithmetic
C. Vector
D. Phasor
Answer : D

28. 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

29. In an ac circuit with XL and R in seriesa the
A. Voltages across R and XL are in phase
B. Voltage across R lags the voltage across XLby 90°
C. Voltages across R and XL are 180° outof-phase
D. Voltage across R leads the voltage across XLby 90°
Answer : B

30. If a coil has a Q of 10a it means that
A. The energy stored in the magnetic field of the coil is 10 times the energy wasted in its resistance
B. The energy wasted in its resistance is 10 times the energy stored in the magnetic field of the coil
C. It is a low Q coil
D. It is a high Q coil
Answer : A

31. In a pure capacitancea
A. Current leads voltage by 90�
B. Current leads voltage by 180�
C. Current lags voltage by 90�
D. Current lags voltage by 180�
Answer : A

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

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

34. Which of the following is not considered a physical factor affecting resistance?
A. Length
B. Material type
C. Temperature
D. Cross-sectional
Answer : C

35. 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

36. 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

37. 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

38. If voltage across the plates of 2 F capacitor is increased by 4 Va then charge on the plates will
A. Decrease by 2 C
B. Increase by 2 C
C. Decrease by 4 C
D. Increase by 4C
Answer : D

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

40. 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

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

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

43. 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

44. 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

45. 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

46. The hot resistance of an incandescent lamp is about ___ times its cold resistance.
A.
B.
C.
D.
Answer : A

47. The impedance in the study of electronics is represented by resistan
A. Inductance
B. Capacitance
C. Inductance and capacitance
D. Reactance
Answer : D

48. What is the total capacitance of 10 capacitorsa each of 20 F in series?
A. 200 F
B. 2 F
C. 100 F
D. 0.5 F
Answer : B

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

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