CEA Electrical Theory & Fundamentals 2 — Questions and Answers
Question 1: A 120V circuit has a resistance of 40 ohms. What is the power dissipated?
- 360 W (Correct answer)
- 480 W
- 240 W
- 720 W
Correct answer: 360 W
Power = V²/R = 120²/40 = 14400/40 = 360 W.
Question 2: Which material is considered the best conductor of electricity?
- Copper
- Silver (Correct answer)
- Gold
- Aluminum
Correct answer: Silver
Silver has the highest electrical conductivity of all metals, though copper is more commonly used due to cost.
Question 3: In a parallel circuit with three 60-ohm resistors, what is the total resistance?
- 20 Ω (Correct answer)
- 180 Ω
- 60 Ω
- 30 Ω
Correct answer: 20 Ω
For equal resistors in parallel, total resistance = R/n = 60/3 = 20 Ω.
Question 4: What happens to current flow when temperature increases in a copper conductor?
- Current increases
- Current decreases (Correct answer)
- Current remains the same
- Current reverses direction
Correct answer: Current decreases
As temperature rises, resistance of copper increases, which reduces current flow for a given voltage.
Question 5: Kirchhoff's Current Law (KCL) states that:
- The sum of voltages around a loop equals zero
- The sum of currents entering a node equals the sum leaving (Correct answer)
- Current is proportional to voltage
- Resistance increases with temperature
Correct answer: The sum of currents entering a node equals the sum leaving
KCL states that the algebraic sum of all currents at a node is zero — what enters must leave.
Question 6: What is the unit of electrical charge?
- Ampere
- Volt
- Coulomb (Correct answer)
- Watt
Correct answer: Coulomb
The coulomb (C) is the SI unit of electric charge; one ampere equals one coulomb per second.
Question 7: A capacitor in a DC circuit, once fully charged, acts as:
- A short circuit
- An open circuit (Correct answer)
- A resistor
- A voltage source
Correct answer: An open circuit
A fully charged capacitor blocks DC current flow, behaving like an open circuit in steady state.
CEA Electrical Theory & Fundamentals 2
A 120V circuit has a resistance of 40 ohms.
What is the power dissipated?