C

Coulomb

F = kq₁q₂/r² (Coulomb's law); 1 C = charge of ~6.242 × 10¹⁸ protons
Quick Reference
Formula / NotationF = kq₁q₂/r² (Coulomb's law); 1 C = charge of ~6.242 × 10¹⁸ protons
Also Known AsC, unit of charge, SI charge unit

What is Coulomb?

The coulomb (C) is the SI unit of electric charge, equal to the charge transported by a current of one ampere in one second. In Faraday's laws of electrolysis, one faraday (96,485 C) is the charge of one mole of electrons. Coulomb's law describes the electrostatic force between charged particles: F = kq₁q₂/r².

Formula & Notation

F = kq₁q₂/r² (Coulomb's law); 1 C = charge of ~6.242 × 10¹⁸ protons

Other Names / Synonyms: C, unit of charge, SI charge unit

Properties & Characteristics

The coulomb (C) is the SI unit of electric charge. It is defined as the charge transported by a current of 1 ampere in 1 second (Q = It). The elementary charge (e) = 1.602 × 10⁻¹⁹ C; one mole of electrons carries 96,485 C (1 Faraday). Coulomb's law describes the electrostatic force between charges: F = kq₁q₂/r². In electrochemistry, the amount of substance electrolysed is directly proportional to charge passed (Faraday's laws).

Uses & Applications

Coulombs are the fundamental unit in all electrochemical calculations (Faraday's laws of electrolysis), in capacitor energy storage (E = ½CV²), in dosimetry (radiation exposure), and in understanding ion-ion interactions in electrolyte solutions (Coulombic interactions).

Safety Information

No direct safety concern for the unit. Large charge transfers (lightning, capacitor discharge) are lethal. Electrochemical cells operating at high current (many amperes) can cause severe electrical burns and hydrogen/oxygen evolution hazards.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Coulomb
Formula F = kq₁q₂/r² (Coulomb's law); 1 C = charge of ~6.242 × 10¹⁸ protons
Synonyms C, unit of charge, SI charge unit

Frequently Asked Questions

The coulomb (C) is the SI unit of electric charge, equal to the charge transported by a current of one ampere in one second. In Faraday's laws of electrolysis, one faraday (96,485 C) is the charge of one mole of electrons. Coulomb's law describes the electrostatic force between charged particles: F = kq₁q₂/r².

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