Electric charge

Electric charge is a fundamental property of matter that exists in two forms, known as positive and negative charge. The presence of charge gives rise to electromagnetic force, one of the four fundamental forces of nature.

Overview

Electric charge is a characteristic property of many subatomic particles. The charges of free-standing particles are integer multiples of the elementary charge e; we say that the particles are quantized. The electron, the lightest stable particle carrying non-zero electric charge, carries a charge of −1. The proton has charge +1. Charged particles whose charges have the same sign repel one another, and particles whose charges have different signs attract.

Properties

Electric charge is conserved – the net electric charge of an isolated system remains constant. The system may change by the continuous creation and destruction of particle-antiparticle pairs, but the total charge remains constant.

Units

The SI derived unit of electric charge is the coulomb (C). In electrical engineering, it is also common to measure charge in micro- or milliampere-hours (mAh or Ah). In physics, the elementary charge, the charge of a proton, is used as a unit.

See also

• Electromagnetism
• Coulomb's law
• Electric field
• Electric potential
• Electrostatics

References

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  Positive and negative charges
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  Electric field lines and equipotentials
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  Positive charge
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  Negative charge
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