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Question (11)

QN0028906

A current carrying coil attracts iron pins. Which statement best explains this?

(A) Current produces cooling effect
(B) Coil behaves like a magnet
(C) Pins become conductors only
(D) Wire becomes positively charged permanently

Correct Answer: B

Explanation:

Current carrying coils act like electromagnets.

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Question (12)

QN0028907

Why are rechargeable batteries considered environmentally better than disposable cells?

(A) They contain no chemicals
(B) They can be reused many times
(C) They produce unlimited electricity
(D) They work without electrolyte

Correct Answer: B

Explanation:

Reusing batteries reduces waste and pollution.

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Question (13)

QN0028908

A student keeps a nichrome wire connected to a battery for a longer time. The wire becomes hotter mainly because

(A) heat production depends on duration of current flow
(B) resistance becomes zero
(C) wire changes into magnet
(D) current stops flowing

Correct Answer: A

Explanation:

Longer current flow produces more heat.

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Question (14)

QN0028909

A dry cell stops working after long use because

(A) its magnetic field disappears
(B) chemicals inside get exhausted
(C) zinc changes into plastic
(D) current freezes inside the cell

Correct Answer: B

Explanation:

Chemical reactants are gradually used up during electricity generation.

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Question (15)

QN0028910

Which observation best proves the heating effect of electric current?

(A) Compass needle deflects
(B) Wire becomes warm after current flows
(C) Magnet attracts iron clips
(D) Bulb holder changes colour

Correct Answer: B

Explanation:

Heating effect causes conductors to become warm.

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Question (16)

QN0028911

A student increases the number of cells connected to a heating wire. What is the most likely effect?

(A) Wire produces less heat
(B) Wire becomes cooler
(C) Wire produces more heat
(D) Resistance disappears completely

Correct Answer: C

Explanation:

More cells generally increase current and heating effect.

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Question (17)

QN0028912

Which combination is necessary for producing electricity in a simple chemical cell?

(A) Plastic sheet and paper
(B) Electrodes and electrolyte
(C) Compass and magnet
(D) Switch and resistor only

Correct Answer: B

Explanation:

Chemical cells need electrodes and electrolyte for reactions.

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Question (18)

QN0028913

A student accidentally uses a very thin wire in household wiring. What danger may occur?

(A) Excessive heating and fire risk
(B) Permanent cooling
(C) Loss of magnetism in appliances
(D) Increase in electrolyte strength

Correct Answer: A

Explanation:

Thin wires have greater resistance and may overheat.

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Question (19)

QN0028914

Migratory birds are believed to travel correctly over long distances mainly because they can detect

(A) Earth’s magnetic field
(B) heat from sunlight only
(C) resistance in air
(D) sound produced by oceans

Correct Answer: A

Explanation:

Many migratory birds use Earth’s magnetic field for navigation.

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Question (20)

QN0028915

Which statement correctly explains the working of a battery-operated torch?

(A) Electrical energy changes into chemical energy only
(B) Chemical energy in cells changes into electrical energy
(C) The bulb stores electricity permanently
(D) Magnetic effect alone produces light

Correct Answer: B

Explanation:

Cells convert chemical energy into electrical energy which lights the bulb.

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Question (11)

A current carrying coil attracts iron pins. Which statement best explains this?

Explanation:

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Question (12)

Why are rechargeable batteries considered environmentally better than disposable cells?

Explanation:

Link:

Question (13)

A student keeps a nichrome wire connected to a battery for a longer time. The wire becomes hotter mainly because

Explanation:

Link:

Question (14)

A dry cell stops working after long use because

Explanation:

Link:

Question (15)

Which observation best proves the heating effect of electric current?

Explanation:

Link:

Question (16)

A student increases the number of cells connected to a heating wire. What is the most likely effect?

Explanation:

Link:

Question (17)

Which combination is necessary for producing electricity in a simple chemical cell?

Explanation:

Link:

Question (18)

A student accidentally uses a very thin wire in household wiring. What danger may occur?

Explanation:

Link:

Question (19)

Migratory birds are believed to travel correctly over long distances mainly because they can detect

Explanation:

Link:

Question (20)

Which statement correctly explains the working of a battery-operated torch?

Explanation:

Link:

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