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Question (21)

QN0021

In a torch using an incandescent lamp, reversing the connections of the lamp terminals with the cell terminals will

(A) stop the lamp from glowing
(B) damage the lamp immediately
(C) still allow the lamp to glow
(D) melt the wires

Correct Answer: C

Explanation:

Incandescent lamps glow regardless of terminal direction.

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Question (22)

QN0022

A student observes that an LED glows in one arrangement but not after interchanging the wires. This shows that an LED

(A) has no terminals
(B) allows current in one direction only
(C) produces electricity
(D) works without a battery

Correct Answer: B

Explanation:

LEDs conduct current only in one direction.

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Question (23)

QN0023

Which component of a torch is mainly responsible for opening or closing the circuit?

(A) Lamp
(B) Battery
(C) Switch
(D) Filament

Correct Answer: C

Explanation:

The switch opens or closes the circuit.

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Question (24)

QN0024

In a correctly connected battery of two cells, the free terminals at the ends are

(A) both positive
(B) both negative
(C) one positive and one negative
(D) both disconnected

Correct Answer: C

Explanation:

A battery has one free positive and one free negative terminal.

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Question (25)

QN0025

A student connects one wire from the cell to the metal case of the lamp and another wire to the metal tip at the centre of the lamp base. What is likely to happen if the connections are complete?

(A) The lamp glows
(B) The lamp breaks instantly
(C) The cell melts
(D) Nothing happens

Correct Answer: A

Explanation:

Proper terminal connections complete the circuit.

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Question (26)

QN0026

Why are the two thick wires inside an incandescent lamp fixed carefully without touching each other?

(A) To increase battery size
(B) To avoid breaking the glass bulb
(C) To keep the two terminals separate
(D) To make the lamp waterproof

Correct Answer: C

Explanation:

The terminals must remain separate for proper current flow.

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Question (27)

QN0027

A student connects both terminals of a lamp to only the positive terminal of a cell. What will happen?

(A) The lamp glows dimly
(B) The lamp glows brightly
(C) The lamp does not glow
(D) The lamp changes colour

Correct Answer: C

Explanation:

Current cannot flow without connection to both terminals of the cell.

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Question (28)

QN0028

Which observation proves that electric current is passing through the filament of an incandescent lamp?

(A) The bulb becomes smaller
(B) The filament glows
(C) The switch cools down
(D) The wires disappear

Correct Answer: B

Explanation:

A glowing filament indicates current flow.

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Question (29)

QN0029

In a torch circuit, what happens when the switch is moved from ON position to OFF position?

(A) The battery gains energy
(B) The circuit is broken
(C) The filament becomes longer
(D) Current increases suddenly

Correct Answer: B

Explanation:

OFF position opens the circuit.

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Question (30)

QN0030

A torch contains two cells and an LED. The LED does not glow even though the cells are new. Which is the best first step to solve the problem?

(A) Break the LED
(B) Reverse the LED connections
(C) Remove the filament
(D) Cut the wires

Correct Answer: B

Explanation:

Incorrect LED polarity prevents glowing.

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Question (21)

In a torch using an incandescent lamp, reversing the connections of the lamp terminals with the cell terminals will

Explanation:

Link:

Question (22)

A student observes that an LED glows in one arrangement but not after interchanging the wires. This shows that an LED

Explanation:

Link:

Question (23)

Which component of a torch is mainly responsible for opening or closing the circuit?

Explanation:

Link:

Question (24)

In a correctly connected battery of two cells, the free terminals at the ends are

Explanation:

Link:

Question (25)

A student connects one wire from the cell to the metal case of the lamp and another wire to the metal tip at the centre of the lamp base. What is likely to happen if the connections are complete?

Explanation:

Link:

Question (26)

Why are the two thick wires inside an incandescent lamp fixed carefully without touching each other?

Explanation:

Link:

Question (27)

A student connects both terminals of a lamp to only the positive terminal of a cell. What will happen?

Explanation:

Link:

Question (28)

Which observation proves that electric current is passing through the filament of an incandescent lamp?

Explanation:

Link:

Question (29)

In a torch circuit, what happens when the switch is moved from ON position to OFF position?

Explanation:

Link:

Question (30)

A torch contains two cells and an LED. The LED does not glow even though the cells are new. Which is the best first step to solve the problem?

Explanation:

Link:

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