Free AC Through Resistor, Capacitor and Inductor MCQs with Answers
76 AC Through Resistor, Capacitor and Inductor MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Alternating current through a resistor, capacitor and inductor involves phase relationships between voltage and current, reactance, impedance and energy transfer. A resistor keeps voltage and current in phase, while a capacitor and inductor produce opposite phase shifts, a distinction used in circuit diagrams and numerical calculations.
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76 questions · page 2 of 4
- A. Zero
- B. 2
- C. 1
- D. Not definite
Explanation: At resonance, the inductive and capacitive reactances are equal and cancel, so the circuit impedance is purely resistive.
Correct answer: 1- A. DC circuit
- B. AC circuits
- C. Both AC and DC circuit
- D. Full wave rectifier circuit
Explanation: A choke coil has high inductive reactance, XL = 2πfL, in an AC circuit and can limit current with relatively little power loss.
Correct answer: AC circuits- A. 220V
- B. 220/ 2V
- C. 110V
- D. 220 √2V
Explanation: The 220 V mains value is an RMS voltage. For a sinusoidal supply, Vpeak = √2 Vrms = √2 x 220 V = 220√2 V, approximately 311 V.
Correct answer: 220 √2V- A. Same
- B. Different
- C. At L will be more than at C
- D. At L will be less than at C
Explanation: Components connected in parallel have the same potential difference across their terminals, regardless of their different reactances.
Correct answer: Same- A. The exact value of the current
- B. RMS value of the current
- C. The net value of the current
- D. The peak value of the current
Explanation: A standard AC ammeter is calibrated to indicate the RMS value of alternating current, which produces the same heating effect as an…
Correct answer: RMS value of the current- A. Lags behind voltage by π/2
- B. Is in phase with voltage
- C. Opposite in phase of voltage by π
- D. Leads forward the voltage by π/2
Explanation: For a pure capacitor, current leads the voltage by π/2, or 90 degrees, because current is proportional to the rate at which voltage…
Correct answer: Leads forward the voltage by π/227. When A.C current passes through a capacitor then the current relationship will be_______________?
- A. The current lead voltage by phase angle is 90 degrees
- B. The voltage leads current by phase angle is 90 degrees
- C. The current lead voltage by phase angle is 45 degrees
- D. The voltage leads current by phase angle is 45 degrees
Explanation: In a capacitive AC circuit, the current leads the voltage by 90 degrees because i = C(dV/dt), so current responds to the changing voltage.
Correct answer: The current lead voltage by phase angle is 90 degrees- A. Twice
- B. One half
- C. Four times
- D. None
Explanation: The LC resonance frequency is f = 1/(2π√(LC)). If capacitance becomes 4C, the denominator becomes √4 = 2 times larger, so the frequency…
Correct answer: One half- A. Resistor
- B. Inductor
- C. Capacitor
- D. All the three
Explanation: This is the correct answer. All three elements-resistor, inductor, and capacitor-are basic and fundamental components of A.C circuits.
Correct answer: All the three- A. From a source which is not the same as the unknown voltage.
- B. From a battery.
- C. From the same source as the unknown voltage
- D. Any of the above
Explanation: The correct answer is option (a) - From a source which is not the same as the unknown voltage.
Correct answer: From a source which is not the same as the unknown voltage.- A. 90o
- B. 0o
- C. 180o
- D. None of these
Explanation: This is the correct answer. In a purely resistive A.C circuit, the current and voltage are in phase with each other, meaning they are…
Correct answer: 0o- A. Leads the voltage by 90o or π/2
- B. Lags behind voltage by 90o or π/2
- C. In phase with voltage
- D. None of the above
Explanation: This is the correct answer. In a circuit with only a capacitor, the current leads the voltage by 90 degrees (π/2 radians) in phase.
Correct answer: Leads the voltage by 90o or π/2- A. In the resistor, I leads V by 90 degrees - In the capacitor, I leads V by 90 degrees
- B. In the resistor, I lags V by 90 degrees - In the capacitor, I leads V by 90 degrees
- C. In the resistor, I and V are in phase - In the capacitor, I leads V by 90 degrees
- D. In the resistor, I and V are in phase - In the capacitor, I lags V by 90 degrees
- E. In the resistor, I lags V by 90 degrees - In the capacitor, I lags V by 90 degrees
Explanation: In a resistor, the current and voltage are in phase because the current flows in the same direction as the voltage.
Correct answer: In the resistor, I and V are in phase - In the capacitor, I leads V by 90 degrees- A. Both XC and XL are doubled
- B. Both XC and XL are halved
- C. XC is doubled and XL reduces to half
- D. XL is doubled and XC reduces to half
- E. Both XC and XL are unchanged
Explanation: The reactance of a capacitor is given by: Xc = 1/ (2πfC) where f is the frequency of the AC supply, and C is the capacitance of the…
Correct answer: XL is doubled and XC reduces to half- A. 30 degrees
- B. 45 degrees
- C. 60 degrees
- D. 90 degrees
- E. 180 degrees
Explanation: In an inverting amplifier configuration, the input signal is applied to the negative input terminal of the operational amplifier.
Correct answer: 180 degrees- A. 100 Hz
- B. 50 Hz
- C. 20 Hz
- D. 10 Hz
- E. 200 Hz
Explanation: The distance traveled by the wave along the X-axis in one complete cycle is the wavelength, which is given as 2 cm in the problem.
Correct answer: 50 Hz37. The phase difference between the current and voltage at resonance in R.L.C series A.C circuit is:
- A. 0
- B. -π/2
- C. -π
- D. π/2
Explanation: At resonance in an RLC series AC circuit, the inductive reactance (XL) and capacitive reactance (XC) are equal and cancel each other out.
Correct answer: 0- A. Very small
- B. Very large
- C. Zero
- D. Infinite
Explanation: The capacitive reactance in a pure capacitive DC circuit is infinite. This is because a steady DC voltage causes the capacitor to charge…
Correct answer: Infinite- A. Large
- B. Small
- C. Zero
- D. Infinite
Explanation: In a capacitive circuit, as the frequency increases, the capacitive reactance (Xc) decreases.
Correct answer: Large- A. Load
- B. Split rings
- C. Commutator
- D. Capacitor
Explanation: The component in a generator that consumes energy is called the load. In the context of electrical systems, a load is any device or…
Correct answer: Load