A switch in a torch circuit is opened (turned off). Explain, in terms of what happens to the electric charges…

Question

A switch in a torch circuit is opened (turned off). Explain, in terms of what happens to the electric charges, why the bulb stops glowing.

Accepted Answer

## Model Answer When the switch is opened, the conducting link between the cell and the bulb is broken. This means the electric circuit is no longer closed (continuous). As a result, the electric charges (electrons) in the metallic wire stop flowing — there is no electric current in the circuit. Since no current flows through the bulb's filament, no heat is produced in it, so the filament does not get hot enough to emit light and the bulb stops glowing. *Source: Chapter 11 – Electricity, Section 11.1 Electric Current and Circuit; Section 11.7.1 Practical Applications of Heating Effect* --- ## Explanation Examiners look for **three distinct points** (1 mark each): 1. Opening the switch **breaks the closed/continuous path** (circuit is incomplete). 2. **Charges/electrons stop flowing** → no electric current. 3. No current means **no heating of filament** → bulb does not glow. Avoid vague phrases like "electricity stops." Be specific: it is the **flow of charges** that stops, and it is t…

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