1000+ Electrical Circuits MCQ for IIFT [Solved]

1. 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

2. 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

3. What does a capacitor store?
A. Voltage
B. Charge
C. Current
D. Power
Answer : B

4. 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

5. 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

6. 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

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

8. Which of the following is a way of decreasing mutual inductance?
A. Moving the coils closer
B. Moving the coils apart
C. Decreasing the number of turns of either coil
D. Increasing the number of turns of either coil
Answer : B

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

10. Which of the following capacitors has the highest cost per F?
A. Plastic
B. Air
C. Mica
D. Electrolytic
Answer : D

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 potential gradient in a cable is maximum in
A. Conductor
B. Outer sheath
C. Insulation
D. Uniformly all over
Answer : A

13. What is the total resistance of a two equal valued resistors in series?
A. The difference of both
B. The product of both
C. Twice as one
D. The sum of their reciprocals
Answer : C

14. High resistance values are a consequence of the ___ of the film.
A. Thickness
B. Length
C. Thinness
D. Area
Answer : C

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

16. What is the cross-sectional are of a conductor whose diameter is 0.001 inch?
A. One micron
B. One angstrom
C. One steradian
D. One circular mil
Answer : D

17. 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

18. 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

19. 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

20. 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

21. 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

22. The capacitance of a capacitor is ___ relative permittivity.
A. Directly proportional to
B. Inversely proportional to
C. Equal to
D. Inversely proportional to the square of
Answer : A

23. 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

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

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

26. 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

27. In Norton�s theorema the short circuit current is obtained by
A. Opening the load terminals
B. Shorting the load terminals
C. Opening the voltage source
D. Shorting the voltage source
Answer : B

28. What is the most convenient way of achieving large capacitance?
A. By using multiplate construction
B. By using air as dielectric
C. By decreasing distance between plates
D. By using dielectric of low permittivity
Answer : A

29. 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

30. The maximum power transfer theorem is used in
A. Power system
B. Electronic system
C. Refrigeration
D. Air conditioning
Answer : B

31. 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

32. Transient period is considered over after
A.
B.
C.
D.
Answer : A

33. 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

34. In dividing or multiplying phasor quantitiesa ___ form is used.
A. Polar
B. Rectangular
C. Trigonometric
D. Exponential
Answer : A

35. A trigger circuit consisting of a capacitor of 0.01 F is connected in series with a resistor. If the circuit requires 100 Vdcto operatea determine the value of the resistor when time constant is 0.009s.
A.
B. 900 k
C. 900 M
D. 900 G
Answer : B

36. An open resistor when checked with an ohmmeter reads
A. Zero
B. Infinite
C. High but within the tolerance
D. Low but not zero
Answer : B

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

38. The farad is not equivalent to which of the following combination of units
A. CV2
B. C2/J
C. C/V
D. J/V2
Answer : A

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

40. 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

41. If two resistances of 9 and 6 are connected in parallela the total resistance is
A.
B.
C.
D.
Answer : D

42. If one resistance in a series connection is opena then
A. The current is zero in all the other resistances
B. The current is maximum in all the other resistances
C. The voltage is zero across the open resistance
D. The voltage is infinite across the open resistance
Answer : A

43. When the movable plates of a gang capacitor completely overlap the fixed platesa the capacitance of the capacitor is
A. Halfway between maximum and minimum
B. Maximum
C. Minimum
D. Zero
Answer : B

44. In an inductive coila the rate of rise of current is maximum
A. Near the final maximum value of current
B. At midvalue of current
C. At half-power points
D. After one time constant
Answer : A

45. Leakage resistance in a capacitor results into
A. Internal heating
B. Internal bleeding
C. Shorter useful life
D. Short-circuiting
Answer : A

46. In a resonant circuita if Q ? 10 resonant frequency _______ bandwidth.
A. Bisects
B. Exceeds
C. Is less than
D. Is equal to
Answer : A

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

48. What is considered as the most important value of a sine wave?
A. Effective value
B. Peak value
C. Average value
D. Instantaneous value
Answer : A

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

50. 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