LADWP Electrical Mechanic Test |
COMPREHENSIVE EXAM BANK WITH ACTUAL
QUESTIONS AND CORRECT VERIFIED
ANSWERS AND WELL ELLABORATED
RATIONALES.
1. Ohm's Law states that voltage equals:
A) Current divided by resistance
B) Current times resistance
C) Resistance divided by current
D) Power times current
Correct Answer: B
Rationale: Ohm's Law is V = I × R, where V is voltage, I is
current, and R is resistance. This fundamental relationship
is essential for understanding electrical circuits.
2. The formula for electrical power in watts is:
A) P = V × R
B) P = I × R
C) P = V × I
D) P = V² × R
Correct Answer: C
,Rationale: Power in watts is calculated as P = V × I. This is
the basic power formula. Other variations include P = I² × R
and P = V² / R, derived from Ohm's Law.
3. A circuit has a voltage of 120V and a current of 5A. What
is the power?
A) 24 W
B) 60 W
C) 600 W
D) 1200 W
Correct Answer: C
Rationale: P = V × I = 120V × 5A = 600W. This is a direct
application of the power formula. Understanding power
calculations is essential for electrical work.
4. A circuit has a resistance of 10Ω and a current of 2A.
What is the power dissipated?
A) 20 W
B) 40 W
C) 100 W
D) 200 W
Correct Answer: B
Rationale: P = I² × R = (2A)² × 10Ω = 4 × 10 = 40W. This
formula is useful when voltage is not directly known but
current and resistance are.
,5. A circuit has a voltage of 240V and a resistance of 20Ω.
What is the power?
A) 12 W
B) 120 W
C) 2880 W
D) 4800 W
Correct Answer: C
Rationale: P = V² / R = (240V)² / 20Ω = 57, = 2,880W.
This formula is useful when current is not directly known.
6. The total resistance in a series circuit with resistors of 5Ω,
10Ω, and 15Ω is:
A) 15 Ω
B) 20 Ω
C) 30 Ω
D) 750 Ω
Correct Answer: C
Rationale: In a series circuit, R_T = R1 + R2 + R3 = 5Ω + 10Ω +
15Ω = 30Ω. Series resistance adds directly.
7. The total resistance in a parallel circuit with resistors of
10Ω and 20Ω is approximately:
A) 6.67 Ω
, B) 10 Ω
C) 15 Ω
D) 30 Ω
Correct Answer: A
Rationale: In parallel, 1/R_T = 1/R1 + 1/R2 = 1/10 + 1/20 =
2/20 + 1/20 = 3/20. R_T = 20/3 = 6.67Ω. Parallel resistance is
always less than the smallest individual resistance.
8. Three resistors of 10Ω each are connected in series. What
is the total resistance?
A) 3.33 Ω
B) 10 Ω
C) 20 Ω
D) 30 Ω
Correct Answer: D
Rationale: R_T = R1 + R2 + R3 = 10Ω + 10Ω + 10Ω = 30Ω. In
series, resistances add together.
9. Three resistors of 30Ω each are connected in parallel.
What is the total resistance?
A) 3.33 Ω
B) 10 Ω
C) 30 Ω
D) 90 Ω
COMPREHENSIVE EXAM BANK WITH ACTUAL
QUESTIONS AND CORRECT VERIFIED
ANSWERS AND WELL ELLABORATED
RATIONALES.
1. Ohm's Law states that voltage equals:
A) Current divided by resistance
B) Current times resistance
C) Resistance divided by current
D) Power times current
Correct Answer: B
Rationale: Ohm's Law is V = I × R, where V is voltage, I is
current, and R is resistance. This fundamental relationship
is essential for understanding electrical circuits.
2. The formula for electrical power in watts is:
A) P = V × R
B) P = I × R
C) P = V × I
D) P = V² × R
Correct Answer: C
,Rationale: Power in watts is calculated as P = V × I. This is
the basic power formula. Other variations include P = I² × R
and P = V² / R, derived from Ohm's Law.
3. A circuit has a voltage of 120V and a current of 5A. What
is the power?
A) 24 W
B) 60 W
C) 600 W
D) 1200 W
Correct Answer: C
Rationale: P = V × I = 120V × 5A = 600W. This is a direct
application of the power formula. Understanding power
calculations is essential for electrical work.
4. A circuit has a resistance of 10Ω and a current of 2A.
What is the power dissipated?
A) 20 W
B) 40 W
C) 100 W
D) 200 W
Correct Answer: B
Rationale: P = I² × R = (2A)² × 10Ω = 4 × 10 = 40W. This
formula is useful when voltage is not directly known but
current and resistance are.
,5. A circuit has a voltage of 240V and a resistance of 20Ω.
What is the power?
A) 12 W
B) 120 W
C) 2880 W
D) 4800 W
Correct Answer: C
Rationale: P = V² / R = (240V)² / 20Ω = 57, = 2,880W.
This formula is useful when current is not directly known.
6. The total resistance in a series circuit with resistors of 5Ω,
10Ω, and 15Ω is:
A) 15 Ω
B) 20 Ω
C) 30 Ω
D) 750 Ω
Correct Answer: C
Rationale: In a series circuit, R_T = R1 + R2 + R3 = 5Ω + 10Ω +
15Ω = 30Ω. Series resistance adds directly.
7. The total resistance in a parallel circuit with resistors of
10Ω and 20Ω is approximately:
A) 6.67 Ω
, B) 10 Ω
C) 15 Ω
D) 30 Ω
Correct Answer: A
Rationale: In parallel, 1/R_T = 1/R1 + 1/R2 = 1/10 + 1/20 =
2/20 + 1/20 = 3/20. R_T = 20/3 = 6.67Ω. Parallel resistance is
always less than the smallest individual resistance.
8. Three resistors of 10Ω each are connected in series. What
is the total resistance?
A) 3.33 Ω
B) 10 Ω
C) 20 Ω
D) 30 Ω
Correct Answer: D
Rationale: R_T = R1 + R2 + R3 = 10Ω + 10Ω + 10Ω = 30Ω. In
series, resistances add together.
9. Three resistors of 30Ω each are connected in parallel.
What is the total resistance?
A) 3.33 Ω
B) 10 Ω
C) 30 Ω
D) 90 Ω
