Electrical Circuits 1000+ MCQ with answer for IBPS PO

1. 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

2. Which of the following does not refer to electrical energy?
A. Volt-ampere
B. Joule
C. Watt-second
D. Volt-coulomb
Answer : A

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

4. 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

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

6. 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

7. What is the total effective capacitance of two 0.25 F capacitors connected in series?
A. 0.125 F
B. 1.25 F
C. 0.50 F
D. 2.5 if
Answer : A

8. And ideal current source has an internal conductance of _____ siem
A. Infinite
B. One
C. Zero
D. One million
Answer : C

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

10. 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

11. 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

12. What is a closed path made of several branches of the network called?
A. Junction
B. Node
C. Terminal
D. Loop
Answer : D

13. If an emf in circuit A produces a current in circuit Ba then the same emf in circuit Bproduces the same current in circuit ? this theorem is known as
A. Maximum power transfer theorem
B. Millman�s theorem
C. Reciprocity theorem
D. Norton�s theorem
Answer : C

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

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

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

17. 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

18. 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

19. Which of the following elements is active?
A. Resistor
B. Inductor
C. Capacitor
D. Ideal voltage source
Answer : D

20. The charging of a capacitor through a resistance follows what law?
A. Linear law
B. Hyperbolic law
C. Inverse-square law
D. Exponential law
Answer : D

21. 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

22. Parallel resonant circuit is sometimes called as
A. Acceptor circuit
B. Rejector circuit
C. Inductive circuit
D. Capacitive circuit
Answer : B

23. In an ac circuit with a resistive branch and an inductive branch in parallela the
A. Voltage across the inductance leads the voltage across the resistance by 90°
B. Resistive branch current is 90° out of phase with the inductive branch current
C. Resistive and inductive branch currents have the same phase
D. Resistive and inductive branch currents are 180° outof-phase
Answer : B

24. 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

25. 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

26. 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

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

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

29. 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

30. 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

31. 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

32. 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

33. A capacitor opposes change in
A. Voltage
B. Current
C. Voltage and current
D. Neither voltage nor current
Answer : A

34. 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

35. When capacitors are connected in parallela the total capacitance is
A. Greater than the largest capacitor
B. Smaller than the largest capacitor
C. Smaller than the smallest capacitor
D. Greater than the smallest capacitor
Answer : A

36. The ohmic value of a resistor with negative temperature coefficient
A. Increases with increasing temperature
B. Increase with decreasing temperature
C. Stays unchanged with temperature change
D. Stays unaffected even with increasing temperature
Answer : B

37. 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

38. 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

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

40. What is the hot resistance of a 100 Wa 220 V incandescent lamp?
A.
B.
C.
D.
Answer : C

41. A linear circuit is one whose parameters
A. Change with change in voltage
B. Change with change in current
C. Do not change with voltage and current
D. Change with change in voltage and current
Answer : C

42. A capacitor consists of two
A. Conductors only
B. Dielectric only
C. Conductors separated by a dielectric
D. Dielectric separated by a conductor
Answer : C

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

44. 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

45. 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

46. 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

47. 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

48. 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

49. 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

50. An open inductor has
A. Zero resistance and infinite inductance
B. Infinite resistance and zero inductance
C. Infinite resistance and infinite inductance
D. Zero resistance and zero inductance
Answer : B