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 16 of 30
- A. Lags by π/2
- B. Leads by π/2
- C. tan-1 1/ωCR
- D. tan-1 ω2/R
Explanation: Let us consider the electric circuit shown below. We have a capacitor and an AC voltage V, represented by the symbol ~, that produces a…
Correct answer: Leads by π/2- A. A
- B. B
- C. C
- D. D
Explanation: In a pure capacitive circuit, the current leads the voltage by 90°In series RC circuit, the current leads the voltage by an angle in…
Correct answer: C- A. Zero
- B. One
- C. Two
- D. Three
Explanation: In an LC parallel resonance circuit, the power factor is the ratio of the real power, or the power that is actually consumed by the…
Correct answer: One- A. Twice
- B. Four times
- C. One fourth
- D. One half
Explanation: We are given that initially a LC circuit has resonant frequency f. If initial capacitance is C and initial inductance is L then the…
Correct answer: One half- A. 60Ω
- B. 90Ω
- C. 32Ω
- D. 42Ω
Explanation: 32ohm100micro farad =100×10^-6Xc=1/2πfC=1/2×3.14×50×100×10^-6=1/0.0314=31.84 OR 32
Correct answer: 32Ω- A. Remains same
- B. Decreases
- C. Increases
- D. Bulb turns off
Explanation: If the capacitor takes a longer time to charge and discharge, the current flowing through the bulb decreases.
Correct answer: Decreases- A. 230 V
- B. 460 V
- C. 400V
- D. None of these
Explanation: For many years, mainland Western Europe has used a mains, 3 phase, electricity supply nominally rated at 380v AC 50Hz while the UK used…
Correct answer: 400V- A. Faraday
- B. Einstein
- C. Maxwell
- D. Enderson
Explanation: This is factual information and must be learned.
Correct answer: Maxwell- A. A
- B. B
- C. C
- D. D
Explanation: Light is an electromagnetic wave: this was realized byMaxwell circa 1864, as soon as the equation c = 1/(e0m0)1/2 = 2.998 X 108m/s was…
Correct answer: B- A. Magnitude
- B. Direction
- C. Magnitude as well as direction
- D. None of the above
Explanation: Alternating current (AC) changes both in magnitude and direction over time.
Correct answer: Magnitude as well as direction- A. AC generator
- B. Radio choke
- C. DC generator
- D. Transformer
Explanation: A transformer is a device which uses the phenomenon of mutual induction to change the values of alternating voltages and currents.
Correct answer: Transformer- A. Any doubler
- B. Any tripler
- C. Any multiplication
- D. None of them
Explanation: A voltage multiplier is a specialized rectifier circuit producing an output that is theoretically an integer times the AC peak input, for…
Correct answer: Any multiplication- A. One half of the input cycle
- B. A portion of the positive half of the input cycle
- C. A portion of the negative half of the input cycle
- D. Both halves of the input cycles
Explanation: The answer is A since the positioning of the diode would ultimately decide whether the positive half is allowed to flow or the negative…
Correct answer: One half of the input cycle- A. Vs > Vp while Is > Ip
- B. Vs < Vp while Is > Ip
- C. Vs = Vp while Is > Ip
- D. Vs > Vp while Is < Ip
Explanation: Step-up transformers increase the voltage and decrease the current.
Correct answer: Vs > Vp while Is < Ip- A. Potential of a conductor is greatly increased with a decrease in the charge in it increase in the charge in it. affecting the charge in it
- B. Potential of a conductor is greatly reduced with an increase in the charge in it.
- C. Potential of a conductor is greatly increased without affecting the charge in it
- D. P.otential of a conductor is greatly reduced without affecting the charge in it
- E. Potential of a conductor is greatly increased with an increase in the charge in it
Explanation: The principle of the capacitor is based on the fact that the potential of a conductor is greatly reduced and its capacity is increased…
Correct answer: P.otential of a conductor is greatly reduced without affecting the charge in it- A. Rectification
- B. Amplification
- C. Doping
- D. Integrated Circuit
Explanation: Rectification is the conversion of alternating current to direct current.
Correct answer: Rectification317. PIV stands for :
- A. Positive inverse voltage
- B. Pawn Bh Integrated voltage
- C. Peak inverse voltage
- D. Peak integrated voltage
Explanation: Peak Inverse Voltage (PIV) or Peak Reverse Voltage (PRV) refer to the maximum voltage a diode or other device can withstand in the…
Correct answer: Peak inverse voltage- A. 1
- B. 2
- C. 3
- D. 4
Explanation: The full-wave rectifier circuit consists of 4 diodes arranged in a tetrahedral connection.
Correct answer: 4- A. 20 V
- B. 10 V
- C. 5 V
- D. 25 V
Explanation: Let V1, V2 and V3 be the voltage across Resistance, Inductance and Capacitance. Then Source Voltage (V) may be written as:
Correct answer: 5 V- A. Lenz's law
- B. Faraday's Law
- C. Self-induction
- D. Ampere's law
Explanation: It works on the principle of Faraday's law of electromagnetic induction.
Correct answer: Faraday's Law