Torch: Cell aur Battery

Class 7 Science · Chapter 3: Bijli: Circuit aur Unke Hisse · NCERT Curiosity section 3.1–3.2.2

Seekho

Jalvidyut bijlighar ki school yatra se pehle Neel ki class bijli ke har upyog ki list banaati hai: khaana banaana (ketli, mixer), roshni (ghar, sadak), yaatayaat (metro, bijli scooter, lift), garam-thanda (pankha, geyser, fridge), manoranjan aur sanchaar (phone, internet). List badhti hi jaati hai!

Saavdhaan: socket, khambe aur generator ki bijli jaanleva ho sakti hai. Unse kabhi prayog mat karo. Prayog ke liye sirf cell aur battery, jaise torch, ghadi aur remote mein. Torch se shuru karte hain: switch ek taraf khiskaao to bulb jalta hai, doosri taraf bujhta hai. Andar do ya zyaada electric cell hain.

Har cell ke do terminal hote hain: chhota dhaatu ka dhakkan positive (+) aur chapti dhaatu ki disc negative (−). Cell bijli urja ka portable srot hai. Circuit chinh mein lambi line + aur chhoti line −.

Do cell wale torch mein bulb tabhi jalta hai jab ek cell ka + agle ke − ko chhuye. Aise jude cells battery banaate hain. Zyaada cells zyaada der aur/ya zyaada urja dete hain. (Phone ke ek cell ko bhi "battery" kehte hain.)

Explore: bijli ke upyog.

1. Bijli ka har upyog sort karo.

Yaad rakho

• Cell ka + terminal (dhakkan) aur − terminal (disc); ye portable urja srot hai.
• Battery = cells + se − jude. Mains bijli se kabhi prayog nahi.

Quick check

Torch chalne ke liye cells kaise lagte hain?

1. ek cell ka + agle ke − se
2. + se +
3. − se −
4. kisi bhi kram mein

Socho

Agar tumhare ilaake mein do din bijli na aaye, to kaunse rozmarra ke kaam sabse mushkil honge?

Practice

Teen levels (easy, medium, hard) ke naye sawaalon se practice karo, kuch hands-on, hints aur hal ke saath. Topic poora karne ke liye pichhle 5 mein se 4 sahi karo.