1. Which of the following materials is a good electrical conductor?
A. Rubber
B. Copper
C. Glass
D. Plastic
Answer: B) Copper
Rationale: Copper is widely used as a conductor due to its low
resistance and high conductivity.
2. What is the typical voltage for residential electrical systems in the
United States?
A. 120V
B. 240V
C. Both A and B
D. 480V
Answer: C) Both A and B
Rationale: U.S. residential systems commonly use 120V for standard
outlets and 240V for larger appliances.
3. What is the function of a relay in an electrical circuit?
,A. Measure current
B. Amplify voltage
C. Act as an electrical switch
D. Store energy
Answer: C) Act as an electrical switch
Rationale: A relay uses an electromagnetic mechanism to open or close
electrical contacts, controlling circuits.
4. In a balanced three-phase system, the current in the neutral wire is:
A. Maximum
B. Zero
C. Equal to phase current
D. Double the phase current
Answer: B) Zero
Rationale: A balanced system cancels neutral current.
5. What is the primary function of an electrical transformer?
A. Increase current
B. Reduce resistance
C. Change voltage levels
D. Measure voltage
Answer: C) Change voltage levels
, Rationale: Transformers adjust voltage up or down to suit specific
applications.
6. Which component is used to reduce the voltage in a circuit?
A. Transformer
B. Resistor
C. Capacitor
D. Inductor
Answer: A) Transformer
Rationale: A transformer can step down voltage levels for specific
applications.
7. A circuit with no current flow is known as a:
A. Closed circuit
B. Open circuit
C. Parallel circuit
D. Short circuit
Answer: B) Open circuit
Rationale: An open circuit occurs when there is a break or gap,
preventing current flow.
8. In a circuit, resistance is measured in:
A. Rubber
B. Copper
C. Glass
D. Plastic
Answer: B) Copper
Rationale: Copper is widely used as a conductor due to its low
resistance and high conductivity.
2. What is the typical voltage for residential electrical systems in the
United States?
A. 120V
B. 240V
C. Both A and B
D. 480V
Answer: C) Both A and B
Rationale: U.S. residential systems commonly use 120V for standard
outlets and 240V for larger appliances.
3. What is the function of a relay in an electrical circuit?
,A. Measure current
B. Amplify voltage
C. Act as an electrical switch
D. Store energy
Answer: C) Act as an electrical switch
Rationale: A relay uses an electromagnetic mechanism to open or close
electrical contacts, controlling circuits.
4. In a balanced three-phase system, the current in the neutral wire is:
A. Maximum
B. Zero
C. Equal to phase current
D. Double the phase current
Answer: B) Zero
Rationale: A balanced system cancels neutral current.
5. What is the primary function of an electrical transformer?
A. Increase current
B. Reduce resistance
C. Change voltage levels
D. Measure voltage
Answer: C) Change voltage levels
, Rationale: Transformers adjust voltage up or down to suit specific
applications.
6. Which component is used to reduce the voltage in a circuit?
A. Transformer
B. Resistor
C. Capacitor
D. Inductor
Answer: A) Transformer
Rationale: A transformer can step down voltage levels for specific
applications.
7. A circuit with no current flow is known as a:
A. Closed circuit
B. Open circuit
C. Parallel circuit
D. Short circuit
Answer: B) Open circuit
Rationale: An open circuit occurs when there is a break or gap,
preventing current flow.
8. In a circuit, resistance is measured in:
