1. What is a capacitor?
a. Resistor
b. Inductor
c. Energy storage device
d. Conductor
Answer: c. Energy storage device
2. Which unit is used to measure capacitance?
a. Ohm b. Farad
c. Henry
d. Volt
Answer: b. Farad
3. What does the capacitance of a capacitor depend on?
a. Voltage across the capacitor
b. Distance between the plates
c. Area of the plates
d. All of the above
Answer: d. All of the above
4. In a capacitor, the electric field is strongest:
a. Between the plates
b. Outside the plates
c. Inside the plates
d. In the connecting wires
Answer: a. Between the plates
5. What is the formula for capacitance (C) of a parallel plate capacitor?
a. C = Q/V
b. C = V/Q
c. C = εA/d
d. C = Q/εA
Answer: c. C = εA/d
6. The dielectric material in a capacitor is used to:
a. Increase capacitance
b. Decrease capacitance
c. Short-circuit the capacitor
d. None of the above
Answer: a. Increase capacitance
7. What happens to the capacitance if the distance between the plates of a capacitor is increased?
a. Increases
b. Decreases c. Remains the same
d. Depends on the dielectric
Answer: b. Decreases
8. A capacitor is fully charged when:
a. Current is maximum
b. Voltage is maximum
c. Energy is maximum
d. Both voltage and current are zero
Answer: b. Voltage is maximum
9. What is the time constant (τ) of an RC circuit?
a. R/C
b. C/R
c. R × C
d. C × R
Answer: d. C × R
10. In an AC circuit, the capacitive reactance (Xc) is given by:
a. Xc = 1/(2πfC)
b. Xc = 2πfC
c. Xc = R/(2πf)
d. Xc = 1/(2πfR)
Answer: a. Xc = 1/(2πfC)
11. The time taken for a capacitor to charge to approximately 63.2% of its maximum voltage is equal to: a. 1 time constant
b. 2 time constants
c. 3 time constants
d. 4 time constants
Answer: a. 1 time constant
12. Which type of capacitor is commonly used in high-frequency applications?
a. Ceramic capacitor
b. Electrolytic capacitor
c. Tantalum capacitor
d. Variable capacitor
Answer: a. Ceramic capacitor
13. The voltage across the capacitor in an RC charging circuit follows which curve during the charging process?
a. Linear
b. Exponential
c. Parabolic
d. Sinusoidal
Answer: b. Exponential
14. What is the primary purpose of a bypass capacitor in electronic circuits?
a. Store energy
b. Smooth voltage fluctuations
c. Block DC signals
d. Increase resistance
Answer: b. Smooth voltage fluctuations
15. Which factor affects the energy stored in a capacitor the most?
a. Voltage
b. Capacitance
c. Dielectric material
d. Plate area
Answer: b. Capacitance
16. The capacitance of a capacitor is doubled. What happens to the energy stored?
a. Doubled
b. Halved
c. Quadrupled
d. Unchanged
Answer: c. Quadrupled
17. A capacitor with a dielectric material has a capacitance of 10 μF. If the dielectric constant is doubled, what is the new capacitance?
a. 5 μF
b. 10 μF
c. 20 μF
d. 40 μF
Answer: c. 20 μF
18. What is the time constant of an RL circuit?
a. R/L
b. L/R
c. R × L
d. L × R
Answer: a. R/L
19. The energy stored in a capacitor can be calculated using the formula:
a. W = 0.5CV²
b. W = QV
c. W = 0.5QV
d. W = CV²
Answer: a. W = 0.5CV²
20. A capacitor in series with a resistor makes a:
a. Low-pass filter
b. High-pass filter
c. Band-pass filter
d. Notch filter
Answer: a. Low-pass filter
21. Which capacitor type is polarized and should be connected with the correct polarity?
a. Ceramic capacitor
b. Electrolytic capacitor
c. Film capacitor
d. Variable capacitor
Answer: b. Electrolytic capacitor
22. What happens to the charge on a capacitor when it discharges through a resistor?
a. Increases
b. Decreases
c. Remains constant
d. Depends on the resistor value
Answer: b. Decreases
23. The time constant of an RC circuit determines:
a. Rate of charging
b. Rate of discharging
c. Both charging and discharging rates
d. Resistance of the circuit
Answer: c. Both charging and discharging rates
24. In an AC circuit, if the frequency is increased, what happens to the capacitive reactance?
a. Increases
b. Decreases
c. Remains constant
d. Depends on the voltage
Answer: b. Decreases
25. Which factor is crucial for the breakdown voltage of a capacitor?
a. Capacitance
b. Dielectric strength
c. Voltage rating
d. Plate area
Answer: b. Dielectric strength
26. The symbol for a capacitor in a circuit diagram is:
a. I
b. R
c. C
d. L
Answer: c. C
27. What is the purpose of a coupling capacitor in an amplifier circuit?
a. Block DC signals
b. Increase gain
c. Decrease resistance
d. Short-circuit the output
Answer: a. Block DC signals
28. The time constant of an RC circuit is equal to the product of:
a. Resistance and inductance
b. Resistance and capacitance
c. Inductance and capacitance
d. Voltage and current
Answer: b. Resistance and capacitance
29. Which type of capacitor is commonly used for smoothing voltage in power supply circuits?
a. Ceramic capacitor
b. Electrolytic capacitor
c. Tantalum capacitor
d. Film capacitor
Answer: b. Electrolytic capacitor
30. What is the purpose of a decoupling capacitor in electronic circuits?
a. Block AC signals
b. Smooth voltage fluctuations
c. Increase capacitance
d. Short-circuit the circuit
Answer: b. Smooth voltage fluctuations
31. The charging current in an RC circuit is highest at:
a. Start of charging
b. Middle of charging
c. End of charging
d. It remains constant
Answer: a. Start of charging
32. The relationship between voltage (V), current (I), and capacitance (C) in a capacitor is given by:
a. V = IR
b. I = VR
c. V = Q/C
d. I = CQ
Answer: c. V = Q/C
33. The leakage current in a capacitor is mainly due to:
a. Dielectric breakdown
b. Plate separation
c. Imperfections in the dielectric
d. Voltage rating
Answer: c. Imperfections in the dielectric
34. What is the effect of temperature on the capacitance of a capacitor with a ceramic dielectric?
a. Increases with temperature
b. Decreases with temperature
c. Remains constant
d. Depends on the voltage
Answer: b. Decreases with temperature
35. Which capacitor type is known for its stability and low tolerance?
a. Ceramic capacitor
b. Electrolytic capacitor
c. Film capacitor
d. Variable capacitor
Answer: c. Film capacitor
36. The voltage rating of a capacitor indicates:
a. The maximum allowable voltage across the capacitor
b. The minimum allowable voltage across the capacitor
c. The rate of voltage change
d. The capacitance value
Answer: a. The maximum allowable voltage across the capacitor
37. What is the formula for the reactance (Xc) of a capacitor in an AC circuit?
a. Xc = 1/(2πfC)
b. Xc = 2πfC
c. Xc = R/(2πf)
d. Xc = 1/(2πfR)
Answer: a. Xc = 1/(2πfC)
38. The equivalent capacitance of capacitors in series is calculated using the formula:
a. C_eq = C₁ + C₂ + C₃
b. 1/C_eq = 1/C₁ + 1/C₂ + 1/C₃
c. C_eq = C₁ × C₂ × C₃
d. C_eq = C₁ - C₂ - C₃
Answer: b. 1/C_eq = 1/C₁ + 1/C₂ + 1/C₃
39. The charge on a capacitor is directly proportional to:
a. Voltage
b. Current
c. Capacitance
d. Resistance
Answer: a. Voltage
40. Which type of capacitor is commonly used for coupling and bypass applications in audio circuits?
a. Ceramic capacitor
b. Electrolytic capacitor
c. Tantalum capacitor
d. Film capacitor
Answer: b. Electrolytic capacitor
41. The time constant of an RL circuit determines:
a. Rate of charging
b. Rate of discharging
c. Both charging and discharging rates
d. Resistance of the circuit
Answer: b. Rate of discharging
42. What happens to the charge on a capacitor when it is connected to a battery in a closed circuit?
a. Increases
b. Decreases
c. Remains constant
d. Depends on the battery voltage
Answer: a. Increases
43. Which factor does NOT affect the capacitance of a parallel plate capacitor?
a. Voltage
b. Distance between plates
c. Area of plates
d. Permittivity of the dielectric
Answer: a. Voltage
44. In an AC circuit, if the frequency is decreased, what happens to the capacitive reactance?
a. Increases
b. Decreases
c. Remains constant
d. Depends on the voltage
Answer: a. Increases
45. Which type of capacitor is often used for tuning applications in radio circuits?
a. Ceramic capacitor
b. Electrolytic capacitor
c. Tantalum capacitor
d. Variable capacitor
Answer: d. Variable capacitor
46. The capacitance of a capacitor is inversely proportional to:
a. Voltage
b. Current
c. Distance between plates
d. Permittivity of the dielectric
Answer: c. Distance between plates
47. What is the purpose of a feedback capacitor in an amplifier circuit?
a. Block DC signals
b. Increase gain
c. Decrease resistance
d. Short-circuit the input
Answer: a. Block DC signals
48. Which type of capacitor is known for its small size and high capacitance?
a. Ceramic capacitor
b. Electrolytic capacitor
c. Tantalum capacitor
d. Film capacitor
Answer: c. Tantalum capacitor
49. What is the formula for the energy stored in a capacitor?
a. W = 0.5CV²
b. W = QV
c. W = 0.5QV
d. W = CV²
Answer: a. W = 0.5CV²
50. The capacitance of a parallel plate capacitor is directly proportional to:
a. Voltage
b. Distance between plates
c. Area of plates
d. Permittivity of the dielectric
Answer: c. Area of plates
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