NCERT Solutions Curiosity Chapter 3 Chapter opener and Section 3.1 A Torchlight — In-text Questions

Book page 24 Updated on2026-09-05

Q1.
Can you help Nihal by adding some more uses to his lists? Also, suggest some other ways of grouping the uses of electricity.
Answer

Yes. Every heading in Nihal's chart can be made longer, and the whole chart can be re-drawn in other ways.

More uses under his headings:

HeadingMore uses you can add
LightingTube lights, LED bulbs, table lamp, emergency lamp, traffic signals, hospital operation-theatre lamps, decorative lights at Diwali
CookingInduction cooktop, electric rice cooker, roti maker, water purifier, electric tandoor
Heating and CoolingCooler, hair dryer, iron, cold storage for vegetables, air cooler in a bus
TransportationMetro train, e-rickshaw, electric bus, electric scooter, ropeway
CommunicationTelephone, television broadcast, radio station, Wi-Fi router, mobile tower
EntertainmentMusic system, video game, cinema projector, loudspeaker at a mela
OthersTube-well for irrigation, washing machine, sewing machine, X-ray machine, printing press, ATM

Other ways of grouping the uses:

  • By place — home, school, hospital, farm, factory, shop, road.
  • By what electricity is changed into — light (bulb), heat (iron), sound (radio), motion (fan), or a mixture (hair dryer gives heat + motion).
  • By the source used — devices that run on cells/batteries (torch, remote) and devices that run from a wall socket (refrigerator, geyser).
  • By who uses it — household use, farming use, industrial use, medical use, transport use.
Try This: Walk through your own house with a notebook and count the devices that would stop working if the electricity went off. Most students are surprised — the count usually crosses 20.
Q2.
Why does the torch lamp glow in one position of its switch?
Answer

Because in that position the switch completes the circuit.

Inside a torch there is a cell (or battery), a lamp, and a switch, all joined by metal strips and wires. The switch is simply a movable metal piece that either bridges a gap or leaves it open.

  • ON position — the switch closes the gap, so there is an unbroken path from the + terminal of the cell, through the lamp, and back to the – terminal. Current flows through the filament, it gets hot, and the lamp glows.
  • OFF position — the switch leaves an air gap. Air is an insulator, so the path is broken, no current flows and the lamp stays dark.
Why it happens: A lamp does not glow just because a cell is nearby. Current must actually pass through the filament, and current can only flow round a closed loop. Break the loop anywhere — at the switch, at a loose wire, or at a broken filament — and the lamp goes out.
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