1000+ Electrical Circuits Multiple Choice Question Answer [Solved]

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

2. The temperature-resistance coefficient of pure gold is
A.
B.
C.
D.
Answer : A

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

4. 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

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

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

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

10. A capacitance of 6 ��F means
A. 6 pF
B. 6 nF
C. 6 fF
D. 6 aF
Answer : A

11. When two coils of identical reactance are in parallel without mutual inductancea the reactance of the combination is ___ the reactance of each coil.
A. One half
B. Twice
C. Four times
D. One fourth
Answer : A

12. The rms value of a triangular or sawtooth waveform is ___ tim value.
A.
B.
C.
D.
Answer : A

13. 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

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

15. The resistance of an insulator ___ when its temperature is increased.
A. Decreases
B. Remains the same
C. Increases
D. Varies
Answer : A

16. In a complex number 5 + j 10a 10 is called ___ part.
A. Imaginary
B. Real
C. Conjugate
D. Integer
Answer : A

17. 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

18. The result of rust in electrical (wire) connection is
A. Inductance
B. Conductance
C. Impedance
D. Resistance
Answer : D

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

20. Norton�s theorem is ____ Thevenin�s theorem.
A. The same as
B. The converse of
C. Older that
D. More accurate than
Answer : B

21. A resistor wound with a wire doubled back on itself to reduce the inductance.
A. Bifilar resistor
B. Wire-wound resistor
C. Anti-inductive resistor
D. Bleeder resistor
Answer : A

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

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

24. The charging of a capacitor through a resistance obeys
A. Exponential law
B. Logarithmic law
C. Linear law
D. Square law
Answer : A

25. 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

26. 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

27. Under the conditions of maximum power transfera a voltage source is delivering a power of 15 W to the load. What is the power generated by the source?
A. 60 W
B. 30 W
C. 15 W
D. 4 W
Answer : B

28. What is the efficiency under the conditions of maximum power transfer?
A.
B.
C.
D.
Answer : A

29. ³Any resistance R in a branch of a network in which a current I is flowing can be replaced by a voltage equal to IR�. This states
A. Compensation theorem
B. Reciprocity theorem
C. Millman�s theorem
D. Superposition theorem
Answer : A

30. 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

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

32. If three 100-pF capacitors are connected in seriesa then the total capacitance is
A. 300 pF
B. 100 pF
C. 50 pF
D. 33.3 pF
Answer : D

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

34. For maximum power transfera what is the relation between load resistance RL and internal resistance R of the voltage source?
A. RL= 2 r
B. RL= 1.5 r
C. RL= r
D. RL= 3 r
Answer : C

35. 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

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

37. What capacitance exists not through design but simply because two conducting surfaces are relatively close to each other?
A. Surge
B. Stray
C. Natural
D. Normal
Answer : B

38. 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

39. When frequency of an ac wave decreasesa the value of XLin a coil
A. Approaches zero
B. Gets larger positively
C. Gets larger negatively
D. Stays constant
Answer : A

40. 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

41. 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

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

43. 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

44. The graph between an alternating quantity and time is called
A. Sine wave
B. Curve
C. Waveform
D. A plot
Answer : C

45. 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

46. 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

47. A series-parallel combination of identical resistors will
A. Increase the power rating compared with one resistor alone
B. Increase the voltage rating compared with one resistor alone
C. Reduce the voltage rating compared with resistor alone
D. Result in an expensive circuit
Answer : A

48. 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

49. 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

50. 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