📘 Chapter 3 – Electricity: Circuits and their Components

🔹 Part 4: Mixed Conceptual + Revision MCQs (Q76–Q100)

Q76. Which of these is needed for current to flow?

A) Open circuit
B) Closed circuit
C) Plastic wire
D) Rubber pipe

✅ Answer: B) Closed circuit

Q77. The positive terminal of a cell is represented by:

A) Short line
B) Long line
C) Circle with ×
D) Zig-zag

✅ Answer: B) Long line

Q78. Which of these is an application of conductors?

A) To cover wires
B) To stop flow of current
C) To make wires for current flow
D) To prevent leakage

✅ Answer: C) To make wires for current flow

Q79. Which one is a renewable source of electricity?

A) Coal
B) Petrol
C) Wind
D) Diesel

✅ Answer: C) Wind

Q80. Which of these will not allow electricity to pass through?

A) Aluminium foil
B) Copper wire
C) Rubber eraser
D) Iron nail

✅ Answer: C) Rubber eraser

Q81. A bulb glows only when:

A) Circuit is incomplete
B) Switch is open
C) Circuit is complete
D) Battery is absent

✅ Answer: C) Circuit is complete

Q82. Which device measures potential difference?

A) Ammeter
B) Voltmeter
C) Fuse
D) Switch

✅ Answer: B) Voltmeter

Q83. The bulb filament is made of:

A) Iron
B) Tungsten
C) Copper
D) Silver

✅ Answer: B) Tungsten

Q84. Which component is represented by (○✕) in circuit diagrams?

A) Switch
B) Fuse
C) Bulb
D) Battery

✅ Answer: C) Bulb

Q85. Which device prevents damage due to overcurrent?

A) Voltmeter
B) Ammeter
C) Fuse
D) Switch

✅ Answer: C) Fuse

Q86. Which one is a poor conductor?

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

✅ Answer: C) Plastic

Q87. Which type of current is supplied by cells and batteries?

A) Alternating current (AC)
B) Direct current (DC)
C) Both AC and DC
D) No current

✅ Answer: B) Direct current (DC)

Q88. Which one is used to open/close a circuit?

A) Fuse
B) Switch
C) Battery
D) Bulb

✅ Answer: B) Switch

Q89. Tap water conducts electricity because it contains:

A) Sugar
B) Salts and ions
C) Oxygen
D) Nitrogen

✅ Answer: B) Salts and ions

Q90. Which one of these is an insulator?

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

✅ Answer: C) Rubber

Q91. Which of these symbols is used for an ammeter?

A) Circle with A
B) Circle with V
C) Circle with ×
D) Long-short line

✅ Answer: A) Circle with A

Q92. In a circuit, current flows from:

A) Negative to positive (electron flow)
B) Positive to negative (conventional current)
C) Neutral to positive
D) Negative to neutral

✅ Answer: B) Positive to negative (conventional current)

Q93. Which is the unit of resistance?

A) Volt
B) Ohm
C) Watt
D) Ampere

✅ Answer: B) Ohm

Q94. Which of the following is a conductor?

A) Eraser
B) Key (metal)
C) Plastic pen
D) Rubber band

✅ Answer: B) Key (metal)

Q95. Which of these is NOT a correct circuit symbol?

A) Circle with A → Ammeter
B) Circle with V → Voltmeter
C) Circle with × → Fuse
D) Long-short line → Cell

✅ Answer: C) Circle with × → Fuse

Explanation:
Circle with × = Bulb, not fuse.

Q96. A complete path with no break is called:

A) Open circuit
B) Closed circuit
C) Short circuit
D) Magnetic path

✅ Answer: B) Closed circuit

Q97. Why are wires coated with plastic?

A) To make them heavy
B) To increase resistance
C) To prevent electric shocks
D) To increase current

✅ Answer: C) To prevent electric shocks

Q98. Which is the SI unit of electric current?

A) Joule
B) Volt
C) Ampere
D) Watt

✅ Answer: C) Ampere

Q99. Which statement is correct?

A) Distilled water conducts electricity
B) Pure metals are insulators
C) Human body is a conductor
D) Rubber conducts electricity

✅ Answer: C) Human body is a conductor

Q100. Which of these is a neutral substance, neither conductor nor insulator in pure form?

A) Distilled water
B) Lemon juice
C) Salt solution
D) Copper

✅ Answer: A) Distilled water

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