Circuits I
MIDTERM READINESS EXAM
GUIDE
Q&S
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,1. Question: In a series RLC circuit, what happens to the
current at resonance?
- A. It is minimum
- B. It is maximum
- C. It oscillates
- D. It is constant
Answer: B. It is maximum
Rationale: At resonance, the inductive and capacitive
reactances are equal and cancel each other out, resulting in
maximum current in the circuit.
2. Question: What is the phase difference between
voltage and current in an ideal inductor?
- A. 0 degrees
- B. 90 degrees
- C. 180 degrees
- D. 270 degrees
Answer: B. 90 degrees
Rationale: In an ideal inductor, the current lags the
voltage by 90 degrees due to the inductance.
3. Question: When two capacitors are connected in
series, the equivalent capacitance is:
- A. C1 + C2
- B. C1 C2 / (C1 + C2)
- C. C1 C2
- D. 1 / (1/C1 + 1/C2)
Answer: D. 1 / (1/C1 + 1/C2)
Rationale: The equivalent capacitance of capacitors in
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, series is given by the reciprocal of the sum of their
reciprocals.
4. Question: What is the characteristic equation of a
second-order system?
- A. \(s^2 + s + 1 = 0\)
- B. \(s^2 + 2\zeta \omega_n s + \omega_n^2 = 0\)
- C. \(s^3 + 3s + 1 = 0\)
- D. \(s^2 + R/L s + 1/(LC) = 0\)
Answer: B. \(s^2 + 2\zeta \omega_n s + \omega_n^2 =
0\)
Rationale: The characteristic equation represents the
dynamics of second-order systems in control theory.
5. Question: In a parallel RLC circuit, the total impedance
\(Z\) can be expressed as:
- A. \(Z = R + j(X_L - X_C)\)
- B. \(Z = \frac{1}{\frac{1}{R} + \frac{1}{jX_L} +
\frac{1}{jX_C}}\)
- C. \(Z = R + X_L + X_C\)
- D. \(Z = R - jX\)
Answer: B. \(Z = \frac{1}{\frac{1}{R} + \frac{1}{jX_L} +
\frac{1}{jX_C}}\)
Rationale: The impedance in a parallel RLC circuit is
derived from the sum of the reciprocals of the impedances
of the individual components.
### Fill-in-the-Blank Questions
6. Question: The resonant frequency \(f_0\) of a series
RLC circuit is given by the formula: __________.
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