Q1.
How does a switch turn on or off the torchlight?
Answer
A switch works by closing or opening a small gap in the circuit — nothing more.
| Position | What happens inside | State of the circuit | Lamp |
|---|---|---|---|
| ON | A movable metal piece bridges the gap and touches both contacts | Closed | Current flows from + to –, so the lamp glows |
| OFF | The metal piece is moved away, leaving an air gap between the contacts | Open | No current flows, so the lamp does not glow |
A switch can be placed anywhere in a circuit — before the lamp or after it — because breaking the loop at any one point stops the current everywhere in that loop. The switches used for lights and other devices at home work in exactly the same way, though they are designed differently and are covered with insulating material.
Why it happens: Air is an insulator. So an air gap of even a millimetre is enough to stop the current completely. A switch is simply a convenient, safe way of making and removing that gap.