Electric charge properties

 There are only two kinds of electric charges:

• Positive (+): Carried by protons.

• Negative (−): Carried by electrons.

Like charges repel each other, while opposite charges attract each other. This is known as Coulomb’s Law of attraction and repulsion

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2. Additivity of Charges

Electric charge is a scalar quantity, which means charges can be added algebraically. If a body has a charge of +3 C and another has −2 C, the total charge will be:

Total charge = +3 C + (−2 C) = +1 C

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3. Conservation of Charge

Electric charge is always conserved — it cannot be created or destroyed. In any physical or chemical process, the total charge remains constant, even if individual particles gain or lose charge.

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4. Quantization of Charge

Charge is quantized, which means it exists in discrete packets and not in a continuous form. The smallest unit of charge is the charge of an electron, denoted as:

e = 1.6 × 10⁻¹⁹ coulombs

Any charge $Q$ on a body will always be an integer multiple of this basic unit:

$Q = n \cdot e$, where $n$ is an integer

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5. Charge is Invariant

The electric charge on a body is independent of the frame of reference or motion. Whether a charged particle is at rest or moving at high speed, its charge remains the same.

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6. Charges Can Be Transferred

Charges can move from one body to another, especially in conductors. This is the basis of static electricity and electric current.

There are three methods of charge transfer:

• Friction (e.g., rubbing a balloon on hair)

• Conduction (direct contact)

• Induction (without contact)

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7. Force Between Charges: Coulomb’s Law

The force between two charges is given by Coulomb’s Law:

$$F = k \cdot \frac{q_1 \cdot q_2}{r^2}$$