Free Alternating Current MCQs with Answers
592 Alternating Current 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 varies periodically, so phase relationships become essential when current passes through a resistor, capacitor or inductor. The chapter distinguishes resistance from capacitive and inductive reactance, explains phase lead and lag, and connects changing electric and magnetic fields with the production and properties of electromagnetic waves.
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Read the Alternating Current notesFree MDCAT chapter notes with key terms592 questions · page 15 of 30
- A. A
- B. B
- C. C
- D. D
Explanation: Explanation is provided in the picture below.
Correct answer: A- A. A
- B. B
- C. C
- D. D
Explanation: Explanation is provided in the picture below.
Correct answer: B- A. Xc and R
- B. Xc and XL
- C. Xc and L
- D. XL and C
Explanation: Explanation is provided in the picture below.
Correct answer: Xc and XL- A. A
- B. B
- C. C
- D. D
Explanation: Option 1 talks about the equality of reactances at resonance.Option 2 and 3 provide the mathematical expressions for angular frequency and…
Correct answer: D- A. cos θ
- B. sin θ
- C. tan θ
- D. sec θ
Explanation: The power factor is defined by the cosine of the angle between the voltage and current waveforms in an AC circuit.
Correct answer: cos θ- A. 0
- B. 1/2
- C. 1
- D. ∝
Explanation: The impedance of a pure anti-resonant circuit is infinite (∝) at resonance.
Correct answer: ∝- A. Direct current
- B. Alternating current
- C. Both (a) and (b)
- D. None of above
Explanation: A capacitor is a perfect insulator for direct current (DC) because it blocks the flow of DC through it.
Correct answer: Direct current- A. Low
- B. High
- C. Negligible
- D. None of the above
Explanation: In comparison to DC transmission, losses in AC transmission are generally higher.
Correct answer: High- A. Peak values
- B. Square of peak values
- C. Square root of peak values
- D. Virtual values
Explanation: In AC circuits, AC instruments typically indicate virtual values. Virtual values are the effective or RMS (Root Mean Square) values of the…
Correct answer: Virtual values- A. A
- B. B
- C. C
- D. D
Explanation: In an LCR (inductor, capacitor, resistor) AC circuit, the current becomes minimum when the inductive reactance (XL) is equal to the…
Correct answer: B- A. Direct current
- B. Electronic current
- C. Alternating current
- D. Both (a) and (b)
Explanation: A capacitor allows only alternating current (AC) to pass through it continuously.
Correct answer: Alternating current- A. R is large
- B. R is small
- C. R=XL or XC
- D. None of these
Explanation: The sharpness of resonance can be understood better by understanding resonance.
Correct answer: R is small- A. Resonance
- B. Fluctuation
- C. Modulation
- D. Amplitude
Explanation: The method of superimposing an audio signal over the carrier wave is called modulation.
Correct answer: Modulation- A. Leading current
- B. Lagging voltage
- C. Lagging current
- D. Leading voltage
Explanation: At the frequencies lower than resonant frequency, XL < XC or IL > IC , hence the circuit behaves as inductive circuit has lagging power…
Correct answer: Lagging current- A. Double
- B. three times
- C. One
- D. Zero
Explanation: A power factor of 1 indicates that the voltage and current are in phase and have a low-harmonic content.
Correct answer: One- A. Has powerfactor cos φ = I
- B. May not be a leak proof with less resistance
- C. Leak proof with less resistance
- D. None of these
Explanation: Choke coil is a coil with large inductance and small resistance. It is used in an ac circuit in order to reduce or control the current in…
Correct answer: May not be a leak proof with less resistance- A. Inductive reactance
- B. Ohmic resistance
- C. Capacitive reactance
- D. None of these
Explanation: Reactances resist currents without dissipating power, unlike resistors. Inductive reactance increases with frequency and inductance.
Correct answer: Ohmic resistance- A. A
- B. B
- C. C
- D. D
Explanation: RMS" stands for Root Mean Square, and is a way of expressing an AC quantity of voltage or current in terms functionally equivalent to DC.
Correct answer: B- A. 540 Hz to 1600 Hz
- B. 540 Hz to 1500 MHz
- C. 540 KHz to 1600 KHz
- D. None of these
Explanation: The Amplitude Modulated (AM radio) carrier frequencies are in the frequency range 535-1605 kHz.
Correct answer: 540 KHz to 1600 KHz- A. Capacitor
- B. Transistor
- C. Resistor
- D. Inductor
Explanation: Resistor is an element which opposes the flow of current ..capacitor is device used to store an electric charge in form of static field…
Correct answer: Resistor