What is the unit of electrical charge?

The unit of electrical charge is the coulomb (C).

In physics, electrical charge is a fundamental property of matter that causes it to experience a force when placed in an electromagnetic field. The coulomb is the standard unit used to measure this charge. One coulomb is defined as the amount of charge transferred by a current of one ampere flowing for one second. This relationship is expressed mathematically as \( Q = I \times t \), where \( Q \) is the charge in coulombs, \( I \) is the current in amperes, and \( t \) is the time in seconds.

To give you a sense of scale, a single electron carries a very small charge of approximately \(-1.6 \times 10^{-19}\) coulombs. This means that one coulomb of charge is equivalent to the charge of about \(6.25 \times 10^{18}\) electrons.

Understanding the concept of the coulomb is crucial for analysing electrical circuits and phenomena. For example, when you look at a battery, its capacity is often measured in ampere-hours (Ah), which can be converted to coulombs. A 1 Ah battery can deliver a current of one ampere for one hour, which is equivalent to \(3600\) coulombs (since \(1 \text{ hour} = 3600 \text{ seconds}\)).

In practical applications, knowing the amount of charge can help you determine how long a battery will last, how much energy is stored in a capacitor, or how much charge is transferred in a lightning strike. The concept of charge and its unit, the coulomb, is foundational in understanding and working with electrical systems.