BEE Basic Electrical 4 — Questions and Answers
Question 1: Norton's theorem represents a network as:
- A current source in parallel with a resistance (Correct answer)
- A voltage source in series with a resistance
- A capacitor in series with a resistor
- Two current sources in series
Correct answer: A current source in parallel with a resistance
Norton's equivalent is a current source I_N in parallel with R_N at the terminals.
Question 2: The power factor of a purely resistive circuit is:
- 1 (Correct answer)
- 0
- 0.5
- Undefined
Correct answer: 1
In a purely resistive circuit voltage and current are in phase, so PF = cos(0°) = 1.
Question 3: A wire carries 3 A and has a resistance of 0.5 Ω. What is the voltage drop across it?
- 1.5 V (Correct answer)
- 6 V
- 0.167 V
- 3 V
Correct answer: 1.5 V
V = IR = 3 × 0.5 = 1.5 V.
Question 4: Faraday's law of electromagnetic induction states that the induced EMF is proportional to the:
- Rate of change of magnetic flux (Correct answer)
- Magnitude of the magnetic field
- Velocity of the conductor only
- Resistance of the circuit
Correct answer: Rate of change of magnetic flux
Faraday's law: EMF = -dΦ/dt; the induced EMF equals the rate of change of magnetic flux linkage.
Question 5: What is the impedance of a series RLC circuit at resonance?
- Equal to R only (Correct answer)
- Zero
- Maximum
- Equal to X_L + X_C
Correct answer: Equal to R only
At resonance, X_L = X_C, so they cancel and Z = R.
Question 6: The unit of magnetic flux density is:
- Tesla (Correct answer)
- Weber
- Henry
- Gauss per meter
Correct answer: Tesla
Magnetic flux density B is measured in Tesla (T) in the SI system.
Question 7: Superposition theorem is applicable only to:
- Linear circuits (Correct answer)
- Non-linear circuits
- Circuits with only resistors
- Circuits with only capacitors
Correct answer: Linear circuits
Superposition requires linearity; it cannot be applied to circuits with non-linear elements like diodes.
BEE Basic Electrical 4
Norton's theorem represents a network as: