Electricity: Circuits and their Components Part 3: MCQs (Q51–Q75)

📘 Chapter 3 – Electricity: Circuits and their Components

🔹 Part 3: Conductors and Insulators (Q51–Q75)

Q51. Which of the following is a conductor?

A) Plastic
B) Rubber
C) Copper
D) Wood

✅ Answer: C) Copper

Explanation:

Plastic → Insulator.
Rubber → Insulator.
Copper → Good conductor (Correct).
Wood → Insulator.

Q52. Materials that allow electricity to pass through are called:

A) Conductors
B) Insulators
C) Non-metals
D) Semiconductors

✅ Answer: A) Conductors

Q53. Which of these is an insulator?

A) Iron
B) Silver
C) Glass
D) Aluminium

✅ Answer: C) Glass

Q54. Which metal is the best conductor of electricity?

A) Gold
B) Silver
C) Copper
D) Aluminium

✅ Answer: B) Silver

Q55. The material used to cover electric wires is:

A) Copper
B) Aluminium
C) Plastic
D) Silver

✅ Answer: C) Plastic

Explanation:
Plastic is an insulator, used as a protective covering.

Q56. Which of these is NOT a conductor?

A) Water
B) Human body
C) Rubber
D) Iron

✅ Answer: C) Rubber

Q57. Tap water is a conductor because it contains:

A) Oxygen
B) Ions and salts
C) Sugar
D) Alcohol

✅ Answer: B) Ions and salts

Q58. Pure distilled water is:

A) Good conductor
B) Poor conductor
C) Very good conductor
D) Superconductor

✅ Answer: B) Poor conductor

Q59. Which of these is used to prevent electric shocks?

A) Iron
B) Copper
C) Aluminium
D) Rubber gloves

✅ Answer: D) Rubber gloves

Q60. Which of the following conducts electricity in molten state?

A) Salt (NaCl)
B) Plastic
C) Wood
D) Glass

✅ Answer: A) Salt (NaCl)

Q61. Which of the following is a semiconductor?

A) Copper
B) Silicon
C) Iron
D) Rubber

✅ Answer: B) Silicon

Q62. Which of these is an application of insulators?

A) To allow current to flow
B) To prevent leakage of current
C) To increase resistance
D) To reduce conductivity

✅ Answer: B) To prevent leakage of current

Q63. Electric wires are made of copper because it is:

A) Expensive
B) Lightweight
C) Good conductor
D) Insulator

✅ Answer: C) Good conductor

Q64. Which of these is NOT a good conductor?

A) Mercury
B) Aluminium
C) Copper
D) Plastic

✅ Answer: D) Plastic

Q65. Which of these is a bad conductor of electricity?

A) Gold
B) Iron
C) Silver
D) Rubber

✅ Answer: D) Rubber

Q66. The human body is a conductor because it contains:

A) Bones
B) Salts and water
C) Oxygen
D) Nitrogen

✅ Answer: B) Salts and water

Q67. Which metal is commonly used in electric wires?

A) Aluminium
B) Zinc
C) Silver
D) Lead

✅ Answer: A) Aluminium

Q68. Which part of an electric cable conducts electricity?

A) Plastic cover
B) Copper wire
C) Rubber coating
D) Tape

✅ Answer: B) Copper wire

Q69. Which part of an electric cable prevents shock?

A) Plastic cover
B) Copper wire
C) Aluminium core
D) Salt

✅ Answer: A) Plastic cover

Q70. Which of these is a good conductor used in jewellery but not in wires due to cost?

A) Copper
B) Silver
C) Gold
D) Aluminium

✅ Answer: C) Gold

Q71. Which of the following materials is an insulator?

A) Silver
B) Copper
C) Aluminium
D) Wood

✅ Answer: D) Wood

Q72. Which of the following liquids is a conductor?

A) Distilled water
B) Sugar solution
C) Lemon juice
D) Kerosene

✅ Answer: C) Lemon juice

Explanation:
Lemon juice contains citric acid ions, making it conductive.

Q73. Which of these everyday items works as a conductor?

A) Metal spoon
B) Plastic spoon
C) Wooden stick
D) Rubber band

✅ Answer: A) Metal spoon

Q74. Which is NOT a property of insulators?

A) They prevent current leakage
B) They protect from electric shock
C) They allow free flow of current
D) They are used to cover wires

✅ Answer: C) They allow free flow of current

Q75. Which of these is both a conductor and an insulator depending on conditions?

A) Plastic
B) Glass
C) Graphite
D) Silver

✅ Answer: C) Graphite

Explanation:
Graphite conducts electricity due to free electrons, but as carbon it is non-metal – an exception.

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