Current Aur Potential Difference - Class 10 Science

Taar Ke Andar Hota Kya Hai? 🔌

Switch dabao — bulb turant jal jaata hai. Par andar kya bah raha hai?

Taar ke andar electrons hote hain. Aam haalat mein wo idhar-udhar bina kisi disha ke ghoomte rehte hain — jaise bheed mein log. Par jab aap battery jodte hain, toh sab electrons ek hi disha mein khisakne lagte hain. Isi behaav ko electric current kehte hain.

📌 Electric current = ek second mein kisi jagah se guzarne wala charge.

I = Q / t

Ikai (unit): ampere (A).
1 ampere = 1 coulomb / 1 second

🐢 Electrons bahut DHEERE chalte hain — phir bulb turant kyun jalta hai?

Ye chapter ka sabse chaunkane wala sach hai. Taar mein electrons ki asli raftaar lagbhag 1 millimetre per second hoti hai — yani ek chinti se bhi dheeme! Ek electron ko switch se bulb tak pahunchne mein ghante lag jaayenge.

Toh bulb turant kaise jal jaata hai?

Paani ke pipe wali soch: ek lamba pipe pehle se paani se bhara ho. Ek taraf se aap thoda paani daalo — doosri taraf se turant paani nikalne lagega! Wo aapka daala hua paani nahi hai; wo toh pehle se wahan tha.

Taar mein bhi electrons pehle se bhare hote hain. Switch dabate hi dhakka (electric field) lagbhag roshni ki raftaar se poore taar mein pahunch jaata hai, aur saare electrons ek saath khisakne lagte hain.

🔋 Potential Difference — Asli Dhakka

Electrons apne aap nahi chalte. Unhe dhakka chahiye — aur wo dhakka battery deti hai.

Jaise paani oonchai ke farak se bahta hai, waise charge POTENTIAL ke farak se bahta hai. Farak hi sab kuch hai.

📌 Potential difference (V) = ek coulomb charge ko ek bindu se doosre bindu tak le jaane mein kiya gaya kaam.

V = W / Q

Ikai: volt (V). 1 volt = 1 joule / 1 coulomb

Yani "12 volt ki battery" ka matlab hai: har ek coulomb charge ko 12 joule ki energy milti hai.

⚠️ Ek zaroori aur ulta lagne wala sach

Electrons negative hote hain, isliye wo battery ke − se + ki taraf bahte hain.

Par hum current ki disha ulti maante hain — + se − ki taraf! Ise conventional current kehte hain.

Aisa kyun? Kyunki ye niyam Benjamin Franklin ne electron ki khoj se bhi pehle bana diya tha. Baad mein pata chala ki asli behaav ulta hai — par tab tak duniya bhar ki kitaabein aur formule usi par ban chuke the, isliye niyam nahi badla gaya.

Exam ke liye: current hamesha + se − dikhaao. Ye ek "galti" hai jise duniya ne jaan-boojh kar rakha hua hai!

🧮 Hal Kiye Hue Sawaal

📝 Sawaal 1 — Charge Nikaalo

Ek taar mein 0.5 A current 10 minute tak bahta hai. Kitna charge guzra?

Step 1 — samay ko SECOND mein badlo (sabse aam galti!)
t = 10 minute = 10 × 60 = 600 s

Step 2 — formula: I = Q/t → Q = I × t
Q = 0.5 × 600 = 300 C

✅ Jawab: 300 coulomb.

📝 Sawaal 2 — Kitne Electrons?

Upar wale sawaal mein kitne electrons guzre? (ek electron ka charge = 1.6 × 10⁻¹⁹ C)

Hal: n = Q / e
n = 300 / (1.6 × 10⁻¹⁹)
n = 1.875 × 10²¹ electrons

😲 Yani lagbhag 18 lakh crore crore electrons! Aur ye sirf ek chhote se 0.5 A current mein, 10 minute mein.

📝 Sawaal 3 — Kaam Nikaalo

2 coulomb charge ko 12 V ki battery se guzarne mein kitna kaam hota hai?

Hal: V = W/Q → W = V × Q
W = 12 × 2 = 24 J

✅ Jawab: 24 joule.

📝 Practice — Khud Karo

(a) Ek circuit mein 6 C charge 2 second mein guzra. Current kitna hai?
Jawab: I = Q/t = 6/2 = 3 A

(b) 1 × 10¹⁹ electrons ka kul charge kitna hoga?
Jawab: Q = n × e = 10¹⁹ × 1.6 × 10⁻¹⁹ = 1.6 C

🔧 Circuit Ke Symbols

Circuit diagram banane ke liye kuch fix chinh hote hain. Ye poori duniya mein ek jaise hain — isiliye ek japani engineer ka banaya diagram ek bharatiya engineer bhi padh leta hai.

Standard circuit symbols. Ammeter aur voltmeter ka jodne ka tareeka bilkul ulta hai — yahi exam mein poocha jaata hai.

📌 Ammeter SERIES mein kyun? Kyunki use wahi current naapna hai jo circuit mein bah raha hai — toh current ko usme se guzarna hi padega. Iski apni resistance bahut kam honi chahiye, warna wo khud current ghata dega.

📌 Voltmeter PARALLEL mein kyun? Kyunki use do bindu ke beech ka farak naapna hai — toh use dono bindu se judna padega. Iski apni resistance bahut zyada honi chahiye, taaki wo circuit se current chura na le.

⚠️ Bijli ke saath savdhani — ye mazaak nahi hai. Ghar ki supply 220 V ki hoti hai, aur sirf 0.1 A current dil ko rok sakta hai.

🔹 Geela haath lekar switch ya plug ko kabhi mat chhuo — paani bijli chalata hai
🔹 Khule ya kate hue taar ko haath mat lagao
🔹 Ek socket mein bahut saare plug mat lagao
🔹 Agar kisi ko current lag jaaye toh use haath se mat pakdo — pehle main switch band karo, ya lakdi jaisi cheez se hatao

School ke prayog mein hamesha cell ya battery (1.5 V – 6 V) hi istemaal karo — kabhi ghar ki supply se nahi.

🇮🇳 India Connection

Bharat mein ghar ki supply 220-240 V par aur 50 Hz par aati hai. America aur Japan mein 110-120 V chalta hai. Isiliye videsh se laaya hua appliance yahan seedha nahi lagta — converter chahiye hota hai.

Zyada voltage ka faayda kya? Utni hi power ke liye kam current chahiye (kyunki P = VI) — aur kam current ka matlab patle taar aur kam garmi ka nuksaan. Isiliye bijli ghar se ghar tak hazaron volt par bheji jaati hai, aur aapke mohalle ke transformer par utaar kar 220 V ki jaati hai.

Aur "Saubhagya" yojana ke tehat bharat ne 2017-2019 mein lagbhag 2.8 crore gharon tak pehli baar bijli pahunchayi — duniya ka sabse bada bijleekaran abhiyaan.

🧠 Apne Aap Ko Test Karo

Q1. Electric current ka formula kya hai?

Q2. 1 ampere ka kya matlab hai?

Q3. Ek taar mein 2 A current 5 second bahta hai. Charge kitna guzra?

Q4. Conventional current ki disha kya maani jaati hai?

Q5. Voltmeter ko circuit mein kaise jodte hain?

Q6. 3 C charge ko 6 V ki battery se guzarne mein kitna kaam hota hai?

🧊 3D Circuit Bench par electrons ko bahte aur meters ko live badalte dekho!

Open 3D Circuit Bench →

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