Free Circuit Analysis MCQs with Answers
394 Circuit Analysis MCQs from Electrical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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394 questions · page 15 of 20
- A. average voltage
- B. r.m.s. voltage
- C. peak voltage
- D. none of the above
Explanation: AC equipment ratings use RMS voltage because it produces the same heating effect as an equivalent DC voltage.
Correct answer: r.m.s. voltage- A. a sinusoid of the same frequency
- B. a sinusoid of half the original frequency
- C. a sinusoid of double the frequency
- D. not a sinusoid
Explanation: The difference of two sinusoids having the same frequency can be combined into one sinusoid of that same frequency, with a new amplitude…
Correct answer: a sinusoid of the same frequency- A. 2.5
- B. 5
- C. 10
- D. 15
Explanation: Capacitive reactance is Xc = 1/(2πfC), so it is inversely proportional to frequency.
Correct answer: 10- A. the same as frequency
- B. time required to complete one cycle
- C. expressed in amperes
- D. none of the above
Explanation: The period is the time taken by a waveform to complete one full cycle, and it is measured in seconds. It is related to frequency by T = 1/f.
Correct answer: time required to complete one cycle- A. peak value to r.m.s. value
- B. r.m.s. value to average value
- C. average value to r.m.s. value
- D. none of the above
Explanation: For an alternating waveform, form factor is defined as the ratio of its r.m.s. value to its average value, usually the rectified average.
Correct answer: r.m.s. value to average value- A. 100 n
- B. 50 jt
- C. 25 JT
- D. 5 n
Explanation: Angular frequency is ω = 2πf. With f = 50 Hz, ω = 2π(50) = 100π rad/s, corresponding to option a where the symbol is rendered as n.
Correct answer: 100 n- A. purely inductive circuit
- B. R-L circuit
- C. R-C circuit
- D. R-L-C circuit
Explanation: A transient involving two energy-storage elements is associated with an R-L-C circuit, which contains both an inductor and a capacitor.
Correct answer: R-L-C circuit- A. inductance
- B. capacitance
- C. resistance
- D. both A. and B.
Explanation: A pure resistance has voltage and current in phase, so its power factor is cos 0° = 1.
Correct answer: resistance- A. parallel
- B. series
- C. either A. or (b)
- D. none of the above
Explanation: A capacitor is connected in parallel with an inductive load to supply leading reactive current that offsets the lagging reactive current.
Correct answer: parallel- A. capacitance only
- B. inductance only
- C. resistance only
- D. all above
Explanation: A purely resistive AC circuit obeys the same voltage-current relationships and circuit laws as a DC resistive circuit because resistance…
Correct answer: resistance only- A. R/Z
- B. cosine of phase angle difference be-tween current and voltage
- C. kW/kVA
- D. ratio of useful current to total cur¬rent Iw/I
- E. all of these
Explanation: Power factor can be written as cos φ, kW/kVA, R/Z, or Iw/I, since each represents the in-phase component relative to the total.
Correct answer: all of these- A. minimum
- B. maximum
- C. zero
- D. none of the above
Explanation: At series resonance, inductive and capacitive reactances cancel, leaving only the usually small resistance; hence the impedance is at its…
Correct answer: minimum- A. both waves must have same frequency
- B. both waves must have identical peak values
- C. both waves must have zero value at the same time
- D. none of the aboveGet Study Guides
Explanation: A fixed phase difference between two steady sinusoidal waves is meaningful only when they have the same frequency; otherwise their…
Correct answer: both waves must have same frequency- A. square wave
- B. half wave rectified sine wave
- C. triangular wave
- D. sine wave
Explanation: For the same peak value, a square wave remains at its peak magnitude throughout the cycle, so its RMS value equals the peak value.
Correct answer: square wave- A. resistive elements
- B. passive elements
- C. non-linear elements
- D. linear bilateral elements
Explanation: Superposition requires linear circuit elements so that each source produces a response proportional to its magnitude and the responses can…
Correct answer: linear bilateral elements- A. junction currents
- B. battery e.m.fs.
- C. IR drops
- D. both B. and C.
- E. none of the above
Explanation: Kirchhoff’s voltage law states that the algebraic sum of voltage rises and drops around a closed loop is zero.
Correct answer: both B. and C.297. To determine the polarity of the voltage drop across a resistor, it is necessary to know___________?
- A. value of current through the resistor
- B. direction of current through the resistor
- C. value of resistor
- D. e.m.fs. in the circuit
Explanation: Using the passive sign convention, current enters the positive terminal of a resistor, so the current direction identifies the…
Correct answer: direction of current through the resistor- A. Thevenin's theorem
- B. Millman's theorem
- C. Maximum power transfer theorem
- D. None of the above
Explanation: Millman’s theorem combines parallel source branches by adding their algebraic source currents and combining their branch resistances in…
Correct answer: Millman's theorem- A. Thevenin's theorem
- B. Norton's theorem
- C. Superposition theorem
- D. None of the above
Explanation: Superposition theorem states that the response in any branch of a linear network equals the algebraic sum of responses produced by each…
Correct answer: Superposition theorem- A. only variable resistances
- B. only some sources of e.m.f. in it
- C. only two sources of e.m.f. in it
- D. no source of e.m.f. in it
Explanation: A passive network has no independent source of e.m.f. or externally supplied energy; it only absorbs or stores energy through elements…
Correct answer: no source of e.m.f. in it