ISCET DC Circuit Analysis 3 — Questions and Answers
Question 1: In a series-parallel circuit, two 10Ω resistors are in parallel and that combination is in series with a 5Ω resistor. What is the total resistance?
- 10Ω (Correct answer)
- 25Ω
- 5Ω
- 15Ω
Correct answer: 10Ω
Two 10Ω in parallel = 5Ω; 5Ω + 5Ω in series = 10Ω total.
Question 2: Which law states that the total current entering a junction equals the total current leaving that junction?
- Kirchhoff's Current Law (Correct answer)
- Kirchhoff's Voltage Law
- Ohm's Law
- Faraday's Law
Correct answer: Kirchhoff's Current Law
KCL (Kirchhoff's Current Law) is based on conservation of charge at any circuit node.
Question 3: A 12V source delivers 36W to a load. What current flows through the load?
- 3A (Correct answer)
- 4A
- 0.33A
- 432A
Correct answer: 3A
P = V × I, so I = P/V = 36W / 12V = 3A.
Question 4: When using the superposition theorem, what must be done with all independent voltage sources except the one being analyzed?
- Replace them with short circuits (Correct answer)
- Replace them with open circuits
- Double their value
- Leave them unchanged
Correct answer: Replace them with short circuits
Superposition requires deactivating all other independent sources; voltage sources are shorted, current sources are opened.
Question 5: A 1000Ω resistor is color coded as brown-black-red. What is the correct reading?
- 1000Ω (Correct answer)
- 100Ω
- 10000Ω
- 10Ω
Correct answer: 1000Ω
Brown=1, Black=0, Red=multiplier 100: 10 × 100 = 1000Ω.
Question 6: What is the terminal voltage of a 12V battery with 0.5Ω internal resistance delivering 4A?
- 10V (Correct answer)
- 12V
- 14V
- 8V
Correct answer: 10V
Terminal voltage = EMF − (I × r) = 12 − (4 × 0.5) = 12 − 2 = 10V.
Question 7: Two batteries of 9V and 6V are connected series-aiding. What is the total EMF?
- 15V (Correct answer)
- 3V
- 7.5V
- 54V
Correct answer: 15V
Series-aiding means the voltages add: 9V + 6V = 15V total EMF.
ISCET DC Circuit Analysis 3
In a series-parallel circuit, two 10Ω resistors are in parallel and that combination is in series with a 5Ω resistor.
What is the total resistance?