Identify conventional current direction
Scenario
Log maante the ki sooraj earth ka chakkar lagata hai, baad mein pata chala ulta hai.
Kya tumhe pata hai electric current ki direction ke saath bhi aisi hi ek historical misunderstanding hui thi?
Mental model
Conventional current us direction mein hota hai jahan positive charges jaate hain, yaani electrons ka bilkul ulta.
Jab electricity discover hui thi, tab electrons ke baare mein kisi ko nahi pata tha. Scientists ne socha current positive se negative behta hai. Baad mein electrons mile, jo negative se positive aate hain. Par purana convention aaj bhi chal raha hai.
Explanation
Circuit diagrams mein arrow ka nishaan conventional current ko dikhata hai. Ye direction hamesha battery ke positive terminal se nikal kar negative terminal ki taraf jaati hai.
Asliyat mein, current electrons ke flow ki wajah se hota hai. Electrons negative charge carry karte hain, isliye wo negative terminal se positive terminal ki taraf move karte hain. Is asli movement ko hum electron flow kehte hain.
Kyunki electron flow aur conventional current opposite disha mein hote hain, circuit diagrams mein hum hamesha current (I) ko positive se negative travel karte hue darshate hain.
Yeh rule saari physics mein universal hai. Jab tak explicitly 'electron flow' na poocha jaye, current ki direction hamesha positive se negative hi mark ki jaati hai.
Worked example
Problem: In a closed circuit, how is the direction of electric current related to the flow of electrons?
- Electrons negative charge carry karte hain aur negative terminal se repel hote hain.
- Conventional current electrons ke flow ke opposite maana jata hai.
Answer: Opposite to the direction of flow of electrons
Problem: If a stream of positive charges moves from left to right in a wire, what is the direction of conventional current?
- Conventional current wahi hota hai jis direction mein positive charge move karta hai.
- Isliye current ki direction bhi same hogi.
Answer: Left to right
Key points
- Conventional Direction: Flows from the positive terminal to the negative terminal.
- Electron Flow: Electrons actually flow from the negative terminal to the positive terminal.
Common mistakes
- Confusing current with electron flow: Students electrons ki wajah se current arrow negative se positive banate hain. Yaad rakho, I ki direction humesha + se - hoti hai.
Recall questions
- From which terminal of a cell does conventional current leave?
- What is the conventional direction of electric current?
- In which direction do electrons actually flow in a circuit?
Questions & answers
What is the direction of electric current in an electric circuit?
From the positive terminal of the battery to the negative terminal, opposite to the flow of electrons.
Approach: State the historical convention directly.
If a beam of protons moves towards the East, what is the direction of the conventional current?
East
Approach: Conventional current follows the direction of positive charge flow.
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