51 Important MCQ On Capacitor For Competitive Examination

1. A capacitor has a voltage difference of 10 V across the plates. It has stored charges of 1000 micro-coulombs. What is the capacitance value?

1. 100 μF
2. 10 pF
3. 0.01 μF
4. 100 pF

Solution: (1). 100 μF.

Answer Hints: We know that capacitance is given as C = Q / V

Q is the amount of charges stored by the capacitor. V is the voltage in between the plates.

Using the equations, we get – C = (1000 * 10 ^-6) / 10 = 100 μF

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2. The plates of parallel plate capacitor is right angle in shape. Two sides of them are 2 cm in size. The distance in between two plate given as: 0.1 cm. What will be the capacitance value if the permittivity of the dielectric is 10^-11 F/m?

1. 1 x 10^-14 F
2. 2 x 10^-12 F
3. 2 x 10^-14 F
4. 1 x 10^-12 F

Solution: (2). 2 x 10^-12 F. Try to solve without using the hints!.

Answer Hints: The formula of capacitance is given as-

C =ε A/ d

Here C is the capacitance, ε Refers to the medium’s permittivity. d is the distance. The side of the triangles is – 2cm or 0.02m.

The surface area= ½ * 0.02 * 0.02 = 2×10^-4

ε = 10^-11 F/m d = 0.001m

So, C = 2 x 10^-12 F

3. Find out the equivalence capacitance.

1. 1/3 pF
2. 1 pF
3. 3 pF
4. 9 pF

Solution: (4). 9pF.

Answer Hints: As we can see that The connection is in parallel..

The equivalent parallel capacitance is stated as C_eq = C₁ + C₂ + C₃ + … + C_N

So, the equivalent capacitance is = 3+3+3 = 9 pF

4. Find out the equivalence capacitance of the circuit.

1. 1/3 pF
2. 1 pF
3. 3 pF
4. 9 pF

Solution: (2). 1 pF.

Answer Hints: As we can see, the capacitors are in series connection.

The equivalent series capacitance is stated as 1 / C_eq = 1 / C₁ + 1 / C₂ + 1 / C₃ + … + 1 / C_N

So, the equivalent capacitance is = 1 / (1 / 3+1 / 3+1 / 3) = 3/3 = 1 pF

5. A capacitor has a capacitance value of 1 micro-farad. What does it imply?

1. It stores one coulomb of charge
2. It holds 6.24 x 10¹² electrons
3. It stores one volt
4. It stores one A of current

Solution: (2). It holds 6.24 x 10¹² electrons.

6. What is the effect on capacitive reactance values if the capacitors are connected in series?

1. An increase in total Xc
2. A decrease in real Xc
3. No change in real Xc
4. Reactance does not depend on connectivity.

Solution: (1). An increase in total Xc

7. How an electrostatic field varies if the charge difference is given?

1. Plate differential
2. Plate Distance
3. Dielectric Quantity
4. Plate Area

Solution: 4). Plate Area

8. How the capacitance of a parallel plate capacitor can be decreased?

1. Increasing the gap between the plates
2. If the charge of the capacitor is increased.
3. Decreasing the gap between the plates
4. If the charge of the capacitor is decreased.

Solution: (1). Increasing the gap between the plates

9. A capacitor and an output resistor are connected in series. The circuit will function like –

1. Bridge Rectifier
2. Band-stop filter
3. Low pass filter
4. High pass filter

Solution: (4). High pass filter.

10. Which type of material is used between the plates of the capacitor?

1. Diodes
2. Materials with high impedance
3. Plate divider material
4. Dielectric Material

Solution: (4). Dielectric material.

11.  Which material has the highest dielectric value in the below options?

1. Mica
2. Air
3. Paper
4. Wood

Solution: (1). Mica

12. What is the phase difference for voltage and current in a capacitor only circuit?

1. The voltage lead by 90 degrees
2. The current lead by 90 degrees
3. The voltage lag by 180 degrees
4. The voltage and current has no phase differences.

Solution: (2). The current lead by 90 degrees.

13. What is the effect on capacitance if the dielectric constant is decreased?

1. It remains the same
2. It increases
3. It decreases
4. The capacitor does not function.

Solution: (3). It decreases

14. Which of the following is true about capacitor?

1. C = Q / V
2. V = Q * C
3. C = R * I
4. Q = I / V

Solution: (1). C = Q / V 

15. What is the S.I. unit of capacitor?

1. Henry
2. Ohm
3. Volt / Amp
4. Farad

Solution: (4) Farad

16. What is the value of the Q factor of a capacitor?

1. Q = 1 / RC
2. Q = 1 / (RC)^1/2
3. Q = 1 / ωCR
4. Correct option is not given

Solution: (3). 1 / ωCR

17. What is the capacitor’s time constant?

1. τ₀ = 1 / C
2. τ₀ = RC
3. τ₀ = 1/RC
4. τ₀ = C

Solution: (2). τ₀ = RC

18. Comment Truth or False based on the sentence given.

Statement: Air can serve as the dielectric for the capacitor.

1. True
2. False

Solution: (1). True

19. What is dissipation factor for a ceramic capacitor?

1. tan δ = ESR * ωC
2. tan δ = ESR * 1 / C
3. tan δ = 1 / (ESR * ωC)
4. tan δ = ESR * C

Solution: (1). tan δ = ESR * ωC

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20. What type of ceramic capacitor provides higher stability?

1. Class 1 type
2. Class 2 type
3. Ceramic Disc Capacitor
4. MLCC

Solution: (1). Class 1 type

21. Which dielectric is used for tantalum metal?

1. Tantalum Aluminium Di-Oxide
2. Tantalum Niobium Phosphide
3. Tantalum pentoxide
4. Tantalum phosphide

Solution: (3). Tantalum pentoxide

22. Which type of capacitor has the highest CV product?

1. Ceramic capacitor
2. Tantalum electrolytic capacitor
3. Coupling capacitor
4. bypass capacitor

Solutions: (2). Tantalum Electrolytic capacitors.

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23. What is surge voltage?

1. The minimum voltage received from the load.
2. The maximum voltage received from the load.
3. The maximum peak voltage applied.
4. The minimum peak voltage applied.

Solution: (3). The maximum peak voltage applied.

24. Comment Truth or False based on the sentence given.

Statement: Capacitors are polarized.

1. True
2. False

Solution: (1). True

25. How much energy will be stored in a capacitor if the applied voltage is V?

1. ½ CV²
2. ½ CV
3. CV²
4. 1/4 CV²

Solution: (1). ½ CV²

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26. Condenser is currently known as –

1. Filters
2. Rectifiers
3. Capacitors
4. Diodes

Solution: (3). Capacitors

27. How the impedance of a capacitor is represented in Laplace transform?

1. Z(s) = s / C
2. Z(s) = 1 / sC
3. Z(s) = 1 / s²C
4. Z(s) = S² / C

Solution: (2). Z(s) = 1 / sC

28. What will be the effect of increasing the electrode area of a plate capacitor?

1. The capacitance remains the same.
2. The energy stored by the capacitor gets decreased.
3. The capacitance value gets reduced.
4. The energy stored by the capacitor gets increased.

Solution: (4). The energy stored by the capacitor gets increased.

29. Which of the following is the symbol for a bipolar dielectric capacitor?

Solution: (4).

30. Which organization gives the standardization for all electrical components, including capacitors?

1. IEEE(Institute of Electrical and Electronics Engineers)
2. NMEA(National Marine Electronics Association)
3. IEC(International Electrotechnical Commission)
4. Correct option is not given.

Solution: (3).IEC (International Electrochemical Commission).

31. How quality factor is related with Dissipation Factor?

1. Q = 1 / tan δ
2. Q = 1 / tan² δ
3. Q = tan δ
4. Q = 1 / ESR * tan δ

Solution: (1). Q = 1 / tan δ

32. Which type of capacitor provides high volumetric efficiency?

1. Ceramic Capacitors of Class 1
2. Ceramic Capacitors of Class 2
3. Ceramic Capacitors of Class 3
4. Ceramic Capacitors of Class 4

Solution: (2). Ceramic Capacitors of Class 2

33. How does frequency is related to the capacitance of a capacitor?

1. An increase in the frequency will cause a increase in the capacitance.
2. An increase in the frequency will cause a decrease in the capacitance.
3. Increasing the frequency will not affect the capacitance.
4. Decreasing the frequency will decrease the capacitance.

Solution: (2). An increase in the frequency will cause a decrease in the capacitance.

34. What is voltage proof for a ceramic capacitor?

1. The surge voltage
2. The applied voltage
3. The load voltage
4. The rated voltage.

Solution: (4). The rated voltage.

35. When does the resonance occurs in a ceramic capacitor?

1. When the imaginary parts of the capacitor impedance and admittance cancel each other.
2. When the imaginary parts of the capacitor impedance and admittance do not exist.
3. When the imaginary parts of the capacitor impedance have a higher value than admittance.
4. When the imaginary parts of the capacitor impedance have a lower cost than admittance.

Solution: (1) When the imaginary parts of the capacitor impedance and admittance cancel each other.

36. What is the dielectric absorption for a class 1 ceramic capacitor?

1. 1% to 3%
2. 7% to 9%
3. 0.3% to 0.6%
4. 0.1% to 0.3%

Solution: (3). 0.3% to 0.6%

37. A capacitor is rated as 105K 240 V. What is the capacitance of the capacitor?

1. 10 µF
2. 105 µF
3. 240 µF
4. 1 µF

Solution: (4). 1 µF

38. A capacitor is rated as 105M 240 V. What is the capacitor’s tolerance value?

1. ±10%
2. ±20%
3. ±30%
4. ±40%

Solution: (2). ±20%

39. What is MLCC?

1. Multipurpose Liquid Ceramic Capacitors
2. Multipurpose Leakage Ceramic Capacitors
3. Multi-layer Crystalline Capacitors
4. Multi-layer Ceramic Capacitors

Solutions: (4). Multi-layer Ceramic Capacitors

40. Which type of capacitor is used in transistor circuits?

1. Air
2. Bypass
3. Paper
4. Ceramic

Solution: (4). Ceramic

41. Which bridge is used for measuring capacitance?

1. Wheatstone Bridge
2. Schering Bridge
3. Both (A) and (B)
4. Correct option is not given.

Solution: (2). Schering Bridge

42. Which type of capacitor has a short shelf life than others?

1. Electrolytic Capacitor
2. Ceramic Capacitor
3. Both (A) and (B)
4. None of the above

Solution: (1). Electrolytic Capacitor

43. Which type of capacitor is useful in high-frequency circuits?

1. Ceramic capacitors
2. Mica Capacitors
3. Bypass Capacitors
4. Air Capacitors

Solution: (2). Mica capacitors

44. Which type of capacitor is used in R.F. tuning?

1. Ceramic Capacitor
2. Parallel Plate Capacitors
3. Electrolytic capacitors
4. Mica Capacitors

Solution: (3). Electrolytic capacitors

45. Which type of capacitor is used for D.C. voltage?

1. Ceramic Capacitor
2. Parallel Plate Capacitors
3. Electrolytic capacitors
4. Mica Capacitors

Solution: (3). Electrolytic capacitors

46. Where does the electric charge is stored in a capacitor?

1. The Dielectric Material
2. The parallel Plates
3. Correct option is not given.
4. Both (A) and (B)

Solution: (1). The Dielectric Material

47. Comment Truth or False based on the sentence given.

Statement: Both Electric field and magnetic field are associated with capacitors.

1. True
2. False

Solution: (2). False

48. Comment Truth or False based on the sentence given.

Statement: If the voltage across the capacitor is doubled, the energy stored will be doubled.

1. True
2. False

Solution: (1). True

49. What is the value of true power inside a capacitor?

1. More than 0
2. Equals to 0
3. Lies in the range of 0 to 1
4. Correct option is not given

Solution: (2). Equals to 0

50. How many time constants are required to charge a capacitor completely?

1. 5
2. 4
3. 2.5
4. 2

Solution: (1). 5