How Things Work — Electricity & Magnets (VI–VIII) • Topic 1 of 3

Electric Current & Circuits

CTET recap: An electric cell is the source that pushes current; it has two terminals, a positive (+) and a negative (−). Joining two or more cells gives a battery. Current is the flow of charge through a path, and it will only flow when that path is a closed circuit — a complete, unbroken loop from one terminal of the cell, through the wires and the bulb, and back to the other terminal. The instant there is a gap anywhere — the switch is off, a wire comes loose, the bulb's filament is broken (fused) — the circuit is open and no current flows, so the bulb does not glow. A switch is simply a device to make (close) or break (open) the circuit at will. Pedagogy & how it's tested: This topic is almost always tested through the failed-bulb scenario. A child connects everything but the bulb won't light, and you must identify that the circuit is open somewhere. The deeper pedagogy point CTET likes: at this level children should be taught with hands-on activity (actually building a circuit with a cell, wires, bulb and switch) and circuit diagrams introduced only after the real thing — concrete before abstract, in line with the upper-primary learner. Common misconceptions to flag: children think a single wire from one terminal is enough to light a bulb (they miss that a complete loop is needed); they think the cell 'stores' the bulb's light; and they assume a fresh-looking bulb must work even when its filament is broken. Teaching tip CTET rewards: let children predict, then test, then explain — error is diagnostic, not failure.

✅ Solved examples

1. A student connects a bulb to a cell with wires, but the bulb does not glow. The switch is found to be in the OFF position. The circuit is best described as:
An open circuit. The off switch leaves a gap in the loop, so no current can flow and the bulb stays dark. Turning the switch ON closes the circuit and the bulb glows.
2. Two or more electric cells joined together to give a larger supply of current form a:
A battery. A single unit is a cell; several cells connected together make a battery (as in a torch that takes two cells).
3. For a bulb in a torch to light up, the path from the cell through the bulb and back must be:
A complete, unbroken (closed) loop. Current flows only when the circuit is closed; any break anywhere stops the bulb from glowing.
4. A teacher wants Class VII pupils to understand a circuit. The most effective first activity is to:
Let pupils physically build a circuit with a cell, wires, bulb and switch and observe when the bulb glows — concrete hands-on experience first, then introduce the circuit diagram. This matches how upper-primary children learn best.

✏️ Practice — try these, take hints as needed

1. The device used to make or break an electric circuit conveniently is the:
It turns the bulb on and off.
On = closed, Off = open.
A switch
2. A bulb does not glow even though the cell is new and the switch is ON. On checking, the filament of the bulb is broken. The circuit is:
A broken filament is a gap.
No complete path.
An open circuit (no current flows because of the break)
3. The two ends of an electric cell are called its:
One is positive, one is negative.
Terminals (positive + and negative −)
4. Current flows in a circuit only when the circuit is:
Opposite of open/broken.
A complete loop.
Closed (complete)

📝 Topic test — 8 questions

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