1000+ Electrical Circuits Multiple Choice Question Answer [Solved]

1. Metal tin becomes superconductor at approximately
A. 6 K
B. 3.7 K
C. 5 K
D. 4.7K
Answer : B

2. Refers to the outward-curving distortion of the lines of force near the edges of two parallel metal plates that form a capacitor.
A. Skin effect
B. Night effect
C. Edge effect
D. Hall effect
Answer : C

3. 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

4. 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

5. When two in-phase sine waves that have identical frequency and amplitude are added togethera then the result is a sine wave with ___ the amplitude of either.
A. Half
B. Twice
C. Four times
D. One-fourth
Answer : B

6. Delta to wye or wye to delta transformation technique is applied to a ___ network.
A. One-terminal
B. Two-terminal
C. Three-terminal
D. Complex
Answer : C

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

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

9. 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

10. 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

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

12. Which of the following is neither a basic physical law nor deliverable from one?
A. Ohm�s law
B. Coulomb�s law
C. Kirchhoff�s first law
D. Kirchhoff�s second law
Answer : A

13. In an RL series circuita
A. Current lags voltage by less than 90�
B. Current lags voltage by 180�
C. Current lags voltage by 90�
D. Current leads voltage by 90�
Answer : A

14. In an ac circuit with inductive reactance ?, the
A. Phase angle of the circuit is always 45�
B. Voltage across the inductance must be 90� out o f-phase witht he applied voltage
C. Current through the inductance lags its induced voltage by 90�
D. Current through the inductance and voltage across it are180� outof-phase
Answer : C

15. If a certain circuit has a current that is lagging the voltage by 45�a then it displays
A. Pure inductive reactance
B. Resistance and capacitance reactance
C. Resistance and inductive reactance
D. Pure capacitive reactance
Answer : C

16. Which of the following describes the action of a capacitor?
A. Stores electrical energy
B. Opposes changes in current flow
C. Creates a dc resistance
D. Converts ac to dc
Answer : A

17. 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

18. 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

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

20. In an ac circuita the power dissipated as heat depends on
A. Impedance
B. Capacitive reactance
C. Resistance
D. Inductive reactance
Answer : C

21. When the net reactance in a series coil-capacitor circuit is zero at frequency fa the nature of its reactance of frequency 2f is
A. Inductive
B. Capacitive
C. Resistive
D. Infinite
Answer : A

22. 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

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

24. 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

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

26. For parallel capacitorsa total charge is
A. The sum of individual charges
B. Equal to the charge of either capacitors
C. Equal to the product of the charges
D. The quotient of the charges
Answer : A

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

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

29. 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

30. Which of the following dielectric materials makes the lowest-capacitance capacitor?
A. Paper
B. Mica
C. Air
D. Electrolyte
Answer : C

31. 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

32. 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

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

34. Which factor does not affect resistance?
A. Length
B. Resistivity
C. Cross-sectional area
D. Mass
Answer : D

35. A capacitor is basically constructed of
A. Two conductors separated by a dielectric
B. Two dielectric separated by a conductor
C. Conductors and dielectric
D. Conductors and semiconductors
Answer : A

36. 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

37. A rheostat is a form of
A. Variable resistor
B. Variable capacitor
C. Potentiometer
D. Thermocouple
Answer : A

38. 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

39. 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

40. When the temperature of copper wire is increased its resistance is
A. Increased
B. Decreased
C. Constant
D. Zero
Answer : A

41. In a circuita a passive element is one which
A. Supplies energy
B. Receives energy
C. Both supplies and receives energy
D. Attenuates signal
Answer : B

42. For a triangular and sawtooth waveform the rms voltage or current equals
A. 0.707times peak value
B. 0.577 times peak value
C. 0.577times average value
D. 0.707times rms value
Answer : B

43. 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

44. 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

45. 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

46. In a rectangular wavea the peak factor is
A.
B.
C.
D.
Answer : D

47. 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

48. What is the reading of an ohmmeter for a shorted capacitor?
A. Zero
B. Infinity
C. k
D. M
Answer : A

49. When two unequal values of resistors are connected in parallel across a dc sourcea greater current flows through the
A. Higher resistance
B. Lower resistance
C. Higher wattage resistance
D. Lower wattage resistance
Answer : B

50. 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