Charge is an intrinsic scalar property. Like charges repel and unlike charges attract. Charge is additive, conserved and frame independent.

Meaning and origin of charge

Electric charge is a fundamental property of matter that determines how a body participates in electrical interaction. A proton carries positive charge +e, an electron carries negative charge −e, and a neutron has zero net charge. In ordinary charging processes, protons remain bound in nuclei; it is electrons that move from one body to another.

Two kinds
Positive and negative

Interaction
Like repel; unlike attract

SI unit
coulomb (C)

Dimension
[AT]

Essential properties

Additivity: total charge is the algebraic sum of individual charges.
Conservation: charge may move between bodies, but the total charge of an isolated system remains constant.
Quantisation: observable free charge occurs in integral multiples of the elementary charge.
Invariance: charge does not change merely because the observer or charged particle is moving.

q_total=Σq_i, 1 C = 1 A·s

Example: A body with charges +5 μC, −2 μC and −1 μC has net charge +2 μC.

NEET trap: A neutral body is not necessarily uncharged; it normally contains equal total positive and negative charge.

Key takeaway: Charging is a redistribution of electrons, not the creation of electric charge.

Electric Charges and Fields

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