Capacitor Questions and Answers
A capacitor is a key component in electronics and is frequently featured in aptitude questions and answers for exams like GATE, SSC JE, and PSU technical tests. It stores electrical energy in an electric field and plays a vital role in filtering, timing, and energy storage circuits. Understanding capacitor behavior—like charging, discharging, and reactance—is crucial for solving numerical and conceptual questions. This article provides aptitude questions with explanations that simplify the theory and application of capacitors, helping engineering students and aspirants build a strong conceptual foundation for their placement or competitive exams.
Capacitor
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48 questions
31. If a charged capacitor is disconnected from a circuit, it will:
- immediately discharge
- recharge
- remain charged
- leak the charge
32. The strength of an electric field at a given point is proportional to the potential difference on the plates and inversely proportional to the:
- plate separation
- negative plate only
- field strength
- charge difference
33. How is ac current related to ac voltage in a purely capacitive circuit?
- AC current is 0.707 of the ac voltage.
- AC current lags ac voltage.
- AC current is 0.637 of the ac voltage.
- AC current leads ac voltage.
34. For a given charge difference, electrostatic field strength varies according to:
- plate differential
- plate area
- plate distance
- dielectric quantity
35. A capacitor and an output resistor form a series circuit with a square wave applied. The circuit is:
- an integrator
- a differentiator
- a multiplier
- a divider
36. Capacitive reactance values connected in series offer
- an increase in total XC
- a decrease in total XC
- no change in total XC
- total opposition to voltage in the circuit
37. The quantity that represents an ideal capacitor dissipating 0 W of power is
- instantaneous power
- true power
- reactive power
- resistive power
38. If a capacitor is placed across a 20 V source, what will be the amount of charge after 5 tc?
- 5.0 V
- 12.8 V
- 13.5 V
- 20 V
39. What is the impedance of an ac RC parallel circuit if the resistance is 12 ohms and the capacitive reactance equals 5 ohms?
- 0.2 ohms
- 3.5 ohms
- 4.6 ohms
- 13 ohms
40. What is the Q (Quality factor) of a series circuit that resonates at 6 kHz, has equal reactance of 4 kilo-ohms each, and a resistor value of 50 ohms?
- 0.001
- 50
- 80
- 4.0