Electric charge — properties, quantization, conservation

1.8.1 · Physics › Electromagnetism

1. Electric charge kya hai?

DO types kyun hain, ek kyun nahi? Kyunki experiments do alag behaviours dikhate hain: glass ko silk se rub karo → ise positive kaho; plastic ko fur se rub karo → ise negative kaho. Like charges repel karte hain, unlike charges attract karte hain. Ek hi label repulsion aur attraction dono produce kabhi nahi kar sakta.

2. Teen core properties

Figure — Electric charge — properties, quantization, conservation

3. "Kitne electrons" derive karna — first principles se

Hume koi formula nahi di gayi; hum ise build karte hain.

Setup: Charge ka matlab hai "missing ya extra electrons." Har electron magnitude $e$ carry karta hai. Agar $n$ electrons transfer hue, toh total magnitude $e$ ke $n$ copies honi chahiye: $∣ q ∣ = n times e + e + \dots + e = n e ⟹ n = \frac{∣ q ∣}{e}$

4. Conservation worked example

5. Common mistakes (Steel-manned)

Recall Feynman: ek 12-saal ke bachche ko samjhao

Socho LEGO bricks jo do colours mein aate hain — red (+) aur blue (−). Red aur blue bricks ek saath chipakti hain; do reds door dhakelte hain, do blues door dhakelte hain. Har object mein kuch reds aur blues hote hain. Kisi cheez ko "Charge karna" bas kuch blue bricks ek toy se doosre mein move karna hai. Tum sirf whole bricks move kar sakte ho, kabhi aadhi brick nahi (yahi quantization hai). Aur agar tum ek sealed box mein pehle aur baad mein saari bricks count karo, toh reds-minus-blues ki sankhya kabhi nahi badlati (conservation) — tumne sirf unhe rearrange kiya.

Active-recall flashcards

Electric charge ki teen core properties kya hain?

Additivity (scalar, signed), Conservation, Quantization.

Charge scalar kyun hai, vector kyun nahi?

Iska magnitude aur sign hota hai lekin koi direction nahi; charges ko algebraically add karte hain.

Charge quantization ko mathematically state karo.

q = n e

, jahan

n

ek integer hai aur

e = 1.6 \times 1 0^{- 19}

Elementary charge

e

ki value kya hai?

1.602 \times 1 0^{- 19}

1

coulomb mein kitne electrons hote hain?

Lagbhag

6.24 \times 1 0^{18}

(

1/ e

Ek isolated system ke liye charge conservation state karo.

Total charge constant rehta hai;

\sum q_{b e f or e} = \sum q_{a f t er}

Microscopic level par ek body positively charged kaise banti hai?

Electrons remove karke (protons add karke nahi).

Pair production mein nucleus ya doosra particle kyun present hona chahiye?

Recoil momentum absorb karne ke liye taaki energy AUR momentum conserved rahe; vacuum mein akela photon dono nahi kar sakta.

Do identical spheres

+ 8 e

aur

- 2 e

touch karte hain — har ek ka final charge?

+ 3 e

each (total

+ 6 e

equally shared).

Kya koi free particle charge

2.4 \times 1 0^{- 19}

C carry kar sakta hai? Kyun?

Nahi;

n = 1.5

integer nahi hai, quantization violate hoti hai.

Quarks ke

e /3

charge free charge ki quantization kyun nahi todte?

Quarks confined hote hain; koi bhi free particle ka charge

e

se kam nahi hota.

n = |q|/e kya represent karta hai?

Charge

q

produce karne wale excess/deficit electrons ki sankhya.

Connections

Coulomb's Law — do charges kaise force exert karte hain (charge ko source ki tarah use karta hai).
Electric Field — $E$ ka source charge hai.
Conductors and Insulators — electrons kitni aasaani se move karte hain charging enable karne ke liye.
Methods of Charging — friction, conduction, induction.
Gauss's Law — enclosed charge flux determine karta hai (additivity use karta hai).
Conservation Laws in Physics — charge energy aur momentum ke saath.
Atomic Structure — protons aur electrons $\pm e$ ke carriers ki tarah.