Revision Notes for Class 7 Science Chapter 3: Electricity – Circuits and their Components

Condensed revision notes for Class 7 Science Chapter 3: Electricity – Circuits and their Components – Curiosity textbook. These Class 7 Science Chapter 3 notes are ideal for quick revision just before exams.

• Electric circuit: a complete (closed) path along which electric current can flow; an open/incomplete circuit stops current flow.
• Electric cell: a portable source of electrical energy with a positive terminal (metal cap) and negative terminal (flat disc). Battery: two or more cells connected in series (positive-to-negative), adding up their voltage.
• Switch: opens or closes the circuit’s path; it does NOT supply electrical energy itself, only controls whether current can flow.
• Incandescent lamp: glows via a heated filament, works regardless of connection direction. LED: has no filament, has a longer (positive) and shorter (negative) lead, and only glows if connected in the correct direction.
• Series circuit: all components share a single path; if one breaks, the whole circuit stops working (e.g. two lamps end-to-end — if one filament breaks, both go out).
• Conductors (allow current to flow): metals like copper, aluminium, and also graphite (a non-metal exception). Insulators (block current): rubber, plastic, wood, glass, paper, wax.
• Wire insulation: wires are covered in rubber/plastic to prevent current leakage, protect against shocks, and prevent short circuits from wires touching.
• Circuit symbols: a cell/battery = pair of parallel lines (long=positive, short=negative); a bulb = circle with an X inside.

More on this chapter: NCERT Solutions: Class 7 Science Chapter 3 | Extra Questions: Class 7 Science Chapter 3 | Class 7 Science Book | Formulas Handbook

Written by Satish

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