IOWA MASTER ELECTRICIAN EXAM PRACTICE BANK
(NEC-BASED) – 220 QUESTIONS WITH ANSWERS
AND RATIONALES – COMPLETE MOCK EXAM
PREPARATION MATERIAL A+ ALREADY GRADED
LATEST VERSION
1. What is Ohm’s Law?
A. V = I/R
B. V = I × R
C. I = V × R
D. P = V × I
Answer: B
Rationale: Voltage equals current times resistance.
2. Unit of electrical power is:
A. Volt
B. Ampere
C. Watt
D. Ohm
Answer: C
Rationale: Power is measured in watts.
3. Resistance increases when wire length:
A. Decreases
B. Increases
C. Stays constant
D. Becomes copper
Answer: B
Rationale: Longer conductors increase resistance.
4. Current is measured in:
A. Volts
B. Watts
C. Amps
D. Ohms
Answer: C
5. Voltage is also called:
A. Resistance
B. Potential difference
C. Power
,D. Load
Answer: B
6. Electrical power is measured in:
A. Volts
B. Watts
C. Amps
D. Ohms
Answer: B
Rationale: Watts represent electrical power.
7. A short circuit is:
A. High resistance path
B. Low resistance unintended path
C. Open circuit
D. Grounded load
Answer: B
Rationale: A short circuit allows excessive current flow.
8. Voltage drop increases when wire length:
A. Decreases
B. Increases
C. Stays same
D. Becomes insulated
Answer: B
9. The main purpose of a circuit breaker is to:
A. Increase voltage
B. Protect against overcurrent
C. Store energy
D. Reduce resistance
Answer: B
10. A fuse operates by:
A. Magnetic trip
B. Melting element
,C. Capacitor discharge
D. Relay switching
Answer: B
11. Conductors are materials that:
A. Resist current
B. Allow current flow
C. Block voltage
D. Store power
Answer: B
12. Insulators are used to:
A. Increase current
B. Reduce resistance
C. Prevent current flow
D. Generate power
Answer: C
13. Frequency in the U.S. electrical system is:
A. 50 Hz
B. 60 Hz
C. 120 Hz
D. 240 Hz
Answer: B
14. A grounded conductor is typically:
A. Hot wire
B. Neutral wire
C. Equipment frame
D. Bonding jumper
Answer: B
15. The purpose of grounding is to:
A. Increase resistance
B. Stabilize voltage reference
C. Increase load
, D. Reduce ampacity
Answer: B
16. Parallel circuits have:
A. Same current everywhere
B. Same voltage across branches
C. No resistance
D. No load
Answer: B
17. Series circuits have:
A. Same voltage everywhere
B. Same current through all components
C. No resistance
D. Infinite current
Answer: B
18. Power factor relates to:
A. Heat loss
B. Efficiency of power use
C. Wire size
D. Voltage rating
Answer: B
19. A transformer changes:
A. Current only
B. Voltage levels
C. Resistance
D. Frequency
Answer: B
20. Step-up transformer increases:
A. Current
B. Voltage
C. Resistance
(NEC-BASED) – 220 QUESTIONS WITH ANSWERS
AND RATIONALES – COMPLETE MOCK EXAM
PREPARATION MATERIAL A+ ALREADY GRADED
LATEST VERSION
1. What is Ohm’s Law?
A. V = I/R
B. V = I × R
C. I = V × R
D. P = V × I
Answer: B
Rationale: Voltage equals current times resistance.
2. Unit of electrical power is:
A. Volt
B. Ampere
C. Watt
D. Ohm
Answer: C
Rationale: Power is measured in watts.
3. Resistance increases when wire length:
A. Decreases
B. Increases
C. Stays constant
D. Becomes copper
Answer: B
Rationale: Longer conductors increase resistance.
4. Current is measured in:
A. Volts
B. Watts
C. Amps
D. Ohms
Answer: C
5. Voltage is also called:
A. Resistance
B. Potential difference
C. Power
,D. Load
Answer: B
6. Electrical power is measured in:
A. Volts
B. Watts
C. Amps
D. Ohms
Answer: B
Rationale: Watts represent electrical power.
7. A short circuit is:
A. High resistance path
B. Low resistance unintended path
C. Open circuit
D. Grounded load
Answer: B
Rationale: A short circuit allows excessive current flow.
8. Voltage drop increases when wire length:
A. Decreases
B. Increases
C. Stays same
D. Becomes insulated
Answer: B
9. The main purpose of a circuit breaker is to:
A. Increase voltage
B. Protect against overcurrent
C. Store energy
D. Reduce resistance
Answer: B
10. A fuse operates by:
A. Magnetic trip
B. Melting element
,C. Capacitor discharge
D. Relay switching
Answer: B
11. Conductors are materials that:
A. Resist current
B. Allow current flow
C. Block voltage
D. Store power
Answer: B
12. Insulators are used to:
A. Increase current
B. Reduce resistance
C. Prevent current flow
D. Generate power
Answer: C
13. Frequency in the U.S. electrical system is:
A. 50 Hz
B. 60 Hz
C. 120 Hz
D. 240 Hz
Answer: B
14. A grounded conductor is typically:
A. Hot wire
B. Neutral wire
C. Equipment frame
D. Bonding jumper
Answer: B
15. The purpose of grounding is to:
A. Increase resistance
B. Stabilize voltage reference
C. Increase load
, D. Reduce ampacity
Answer: B
16. Parallel circuits have:
A. Same current everywhere
B. Same voltage across branches
C. No resistance
D. No load
Answer: B
17. Series circuits have:
A. Same voltage everywhere
B. Same current through all components
C. No resistance
D. Infinite current
Answer: B
18. Power factor relates to:
A. Heat loss
B. Efficiency of power use
C. Wire size
D. Voltage rating
Answer: B
19. A transformer changes:
A. Current only
B. Voltage levels
C. Resistance
D. Frequency
Answer: B
20. Step-up transformer increases:
A. Current
B. Voltage
C. Resistance
