2026–2027 | 150 Q&A with Rationales | Certification
Study Guide
,Electrical Theory & Fundamentals
Q1. What is the unit of electrical resistance?
A. Volt
B. Ampere
C. Ohm
D. Watt
Answer: C. Ohm
Rationale: The ohm (Ω) is the SI unit used to measure electrical
resistance.
Q2. Which formula represents Ohm's Law?
A. P = VI
B. V = IR
C. P = I²R
D. E = Pt
Answer: B. V = IR
Rationale: Ohm's Law states that voltage equals current multiplied by
resistance.
Q3. A 120 V circuit has a resistance of 20 Ω. What current flows through
the circuit?
A. 2 A
B. 4 A
C. 6 A
D. 8 A
,Answer: C. 6 A
Rationale: Using I = V/R, I = 120/20 = 6 A.
Q4. What is the primary function of a fuse?
A. Increase voltage
B. Limit frequency
C. Interrupt excessive current
D. Improve power factor
Answer: C. Interrupt excessive current
Rationale: A fuse opens the circuit when current exceeds its rated value
for a sufficient period.
Q5. Electrical power in a DC circuit can be calculated using which
formula?
A. P = VI
B. P = V/I
C. P = R/I
D. P = I/V
Answer: A. P = VI
Rationale: Electrical power equals voltage multiplied by current.
Q6. What is the unit of electrical power?
A. Ohm
B. Watt
, C. Coulomb
D. Henry
Answer: B. Watt
Rationale: The watt is the SI unit of power.
Q7. Which quantity is measured in amperes?
A. Voltage
B. Resistance
C. Current
D. Power
Answer: C. Current
Rationale: Amperes measure the rate of electrical charge flow.
Q8. In a series circuit, the current is:
A. Different through each component
B. The same through each component
C. Zero at the source
D. Always higher than voltage
Answer: B. The same through each component
Rationale: A single current path exists in a series circuit, so the same
current flows through each component.
Q9. In a parallel circuit, the voltage across ideal parallel branches is:
A. The same