ISCET DC Circuit Analysis 2 — Questions and Answers
Question 1: Three resistors of 6Ω, 12Ω, and 4Ω are connected in parallel. What is the equivalent resistance?
- 2Ω (Correct answer)
- 22Ω
- 7.33Ω
- 3Ω
Correct answer: 2Ω
1/Req = 1/6 + 1/12 + 1/4 = 2/12 + 1/12 + 3/12 = 6/12, so Req = 2Ω.
Question 2: A 24V battery is connected to a 6Ω and 2Ω resistor in series. What is the voltage drop across the 6Ω resistor?
- 18V (Correct answer)
- 6V
- 12V
- 8V
Correct answer: 18V
Total resistance is 8Ω; current = 24/8 = 3A; V = 3A × 6Ω = 18V.
Question 3: What happens to the total current in a parallel circuit when an additional branch is added?
- Total current increases (Correct answer)
- Total current decreases
- Total current stays the same
- Total current becomes zero
Correct answer: Total current increases
Adding a branch lowers equivalent resistance, so total current from the source increases.
Question 4: A 100Ω resistor and a 900Ω resistor form a voltage divider across 10V. What is the voltage across the 100Ω resistor?
- 1V (Correct answer)
- 9V
- 5V
- 0.1V
Correct answer: 1V
V = 10V × (100/1000) = 1V using the voltage divider formula.
Question 5: Using Kirchhoff's Voltage Law, the algebraic sum of all voltages around any closed loop equals:
- Zero (Correct answer)
- The supply voltage
- The largest voltage drop
- The total resistance
Correct answer: Zero
KVL states that the sum of all EMFs and voltage drops around any closed loop must equal zero.
Question 6: A wire carrying 5A splits into two parallel paths, one drawing 2A. How much current flows through the other path?
- 3A (Correct answer)
- 7A
- 2.5A
- 5A
Correct answer: 3A
By KCL, the sum of currents entering a node equals the sum leaving: 5A = 2A + I, so I = 3A.
Question 7: What is the power dissipated by a 10Ω resistor carrying 3A?
- 90W (Correct answer)
- 30W
- 0.9W
- 300W
Correct answer: 90W
P = I² × R = (3)² × 10 = 9 × 10 = 90W.
ISCET DC Circuit Analysis 2
Three resistors of 6Ω, 12Ω, and 4Ω are connected in parallel.
What is the equivalent resistance?