1000+ Electrical Circuits MCQ for LIC ADO [Solved]

1. 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

2. 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

3. What is the purpose of a load in an electric circuit?
A. To increase the circuit current
B. To decrease the circuit current
C. To utilize electrical energy
D. To make the circuit complete
Answer : C

4. 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

5. When current and voltage arte in phase in an ac circuita the ___ is equal to zero.
A. Resistance
B. Reactance
C. Inductance
D. Capacitance
Answer : B

6. Rationalizing the denominator of a complex number means
A. Eliminating the j component in the denominator
B. Adding j component in the denominator
C. Eliminating the j component in the numerator
D. Adding j component in the numerator
Answer : A

7. Which of the following is not a factor affecting capacitance oor?
A. Area of plates
B. Number of plates
C. Distance between plates
D. Dielectric material used
Answer : B

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

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

10. The power factor of a certain circuit in which the voltage lags behind the current is 80 %. To increase the power to 100 %a it is necessary to add ___ to the circuit.
A. Inductance
B. Capacitance
C. Resistance
D. Impedance
Answer : A

11. 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

12. Resistor with colored bands in the body
A. Wire-wound resistor
B. Carbon-composition resistor
C. Potentiometer
D. Rheostat
Answer : B

13. 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

14. 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

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

16. The value of temperature coefficient ( ) is dependent upon
A. The nature of material and temperature
B. The length of material
C. The cross-sectional area of the material
D. The volume of the material
Answer : A

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

18. The symbol Q refers to
A. Resonance quotient
B. Quality factor
C. Power quotient
D. Qualification test
Answer : B

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

20. What refers to such work at very low temperaturesa near absolute zero?
A. Cryogenics
B. Superconductivity
C. Subsonic
D. Thermionic
Answer : A

21. In a series RLCcircuit
A. Increasing the frequency decreases the resistance
B. Increasing the frequency increases the resistance
C. Both XLand XCchange as frequency changes
D. Impedance will always decrease
Answer : C

22. Which statement is true about a passive circuit?
A. A circuit with neither a source of current nor a source of potential difference
B. A circuit with a voltage source
C. A circuit with a current source
D. A circuit with only resistance as a load
Answer : A

23. If a capacitor is rated for 200V dca what is its effective ac working voltage?
A. 50 V
B. 100 V
C. 200 V
D. 400 V
Answer : C

24. 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

25. 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

26. 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

27. 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

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

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

30. 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

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

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

33. Which of the following represents the energy stored in a cap
A. CV2/2
B. 2Q2/C
C. C2/V
D. CV
Answer : A

34. Which of the following has a positive temperature coefficient?
A. Mica
B. Manganin
C. Silicon
D. Carbon
Answer : B

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

36. The Q-factor of a parallel resonant circuit is also known as
A. Current magnification factor
B. Voltage magnification factor
C. Load factor
D. Leakage factor
Answer : A

37. 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

38. 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

39. Which of the following is the statement of Ohm�s law?
A. Electric current is directly proportional to both voltage and resistance
B. Electric current varies directly as the voltage and inversely as the resistance
C. Electrical power is directly proportional to the resistance and inversely as the current squared
D. Electrical power is directly proportional to both voltage squared and the resistance
Answer : B

40. What refers to the lowest voltage across any insulator that can cause current flow?
A. Conduction voltage
B. Critical voltage
C. Breakdown voltage
D. Voltage capacity
Answer : C

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

42. A capacitor requires 12 C of charge to raise its potential of 3 V. What is the capacitance of the capacitor?
A. 36 F
B. 15 F
C. 0.25 F
D. 4 F
Answer : D

43. A switch designed to have low capacitance between its terminal when open.
A. LOCAP switch
B. AntiLOCAP switch
C. Anticapacitance switch
D. Capacitance switch
Answer : C

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

45. 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

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

47. The ___ of an alternating quantity is defined as the fractional part of a period or cycle through which the quantity has advanced from selected origin.
A. Phase
B. Frequency
C. Amplitude
D. Waveform
Answer : A

48. What increases the resistance of wire at high frequencies?
A. Temperature
B. Voltage
C. Skin effect
D. Insulation
Answer : C

49. 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

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