EIT Electrical Circuits 1 — Questions and Answers
Question 1: According to Ohm's Law, what is the current through a 10Ω resistor with 20V across it?
- 0.5 A
- 2 A (Correct answer)
- 200 A
- 10 A
Correct answer: 2 A
Ohm's Law: I = V/R = 20/10 = 2 A.
Question 2: What is the total resistance of three 6Ω resistors connected in parallel?
- 18 Ω
- 6 Ω
- 2 Ω (Correct answer)
- 3 Ω
Correct answer: 2 Ω
For n equal resistors in parallel: R_total = R/n = 6/3 = 2 Ω.
Question 3: Kirchhoff's Current Law (KCL) states that:
- Voltage around a loop sums to zero
- Current entering a node equals current leaving the node (Correct answer)
- Power consumed equals power supplied
- Impedance is the sum of resistance and reactance
Correct answer: Current entering a node equals current leaving the node
KCL is a statement of charge conservation: the algebraic sum of currents at any node equals zero.
Question 4: What is the impedance of a 100Ω resistor in series with a capacitive reactance of 100Ω?
- 200 Ω
- 100 Ω
- 141.4 Ω (Correct answer)
- 50 Ω
Correct answer: 141.4 Ω
Z = √(R² + Xc²) = √(100² + 100²) = √20000 ≈ 141.4 Ω.
Question 5: The power factor of a purely resistive circuit is:
- 0
- 0.5
- 1 (Correct answer)
- −1
Correct answer: 1
A purely resistive circuit has voltage and current in phase, giving a power factor of cos(0°) = 1.
Question 6: What is the energy stored in a 4H inductor carrying 3A?
- 12 J
- 18 J (Correct answer)
- 6 J
- 36 J
Correct answer: 18 J
Energy stored in an inductor: W = ½LI² = ½(4)(3²) = ½(4)(9) = 18 J.
EIT Electrical Circuits 1
According to Ohm's Law, what is the current through a 10Ω resistor with 20V across it?