Coulomb

Definition

A coulomb (C) is the SI unit of electric charge, representing the amount of charge transported by a constant current of one ampere in one second. One coulomb is equivalent to approximately $6.242 \times 10^{18}$ elementary charges.

5 Must Know Facts For Your Next Test

1. The symbol for coulomb is C.
2. One coulomb is equal to the charge of approximately $6.242 \times 10^{18}$ electrons.
3. In the context of electric fields, a point charge in coulombs is used to calculate the electric field strength using Coulomb's law.
4. When dealing with magnetic forces between parallel currents, the force per unit length between two wires carrying currents I1 and I2 separated by distance d can be expressed using coulombs as part of the interaction formula.
5. A capacitor's capacitance is measured in farads, where one farad equals one coulomb per volt.

Review Questions

• What physical quantity does a coulomb measure?
• How many elementary charges make up one coulomb?
• Describe how a coulomb relates to electric current and time.

Related terms

Ampere:

The SI unit of electric current, defined as one coulomb per second.

Electric Field: A region around a charged particle where a force would be experienced by other charges, often calculated using Coulomb's law.

Capacitance:

\text{The ability of a system to store an electric charge, measured in farads (F), where } \text{1 F} = \text{1 C/V}.