# Definition:Electric Charge

## Definition

**Electric charge** is a physical quantity of matter which causes it to experience a force when near other electrically charged matter.

It is a scalar quantity.

### Quantum

**Electric charge** has been demonstrated to be quantized.

The quantum of electric charge is the elementary charge $\E$:

- $\E = 1.60217 \, 6634 \times 10^{−19}$ coulombs
*exactly*.

This sequence is A081823 in the On-Line Encyclopedia of Integer Sequences (N. J. A. Sloane (Ed.), 2008).

This is so small that to all practical purposes in everyday measurement of electricity, it can be treated as though it were continuous.

### Dimension

The dimension of measurement of **electric charge** is $\mathsf {I T}$.

### Units

The SI unit of **electric charge** is the coulomb $\mathrm C$.

## Sign

The **sign** of an **electric charge** can be one of $2$ types:

### Positive Electric Charge

A **positive electric charge** is an electric charge which is of the same sign as the electric charge on a proton.

When it is necessary to assign a value to a **positive electric charge**, a $+$ (plus) sign is used, and the value assigned is a positive number.

### Negative Electric Charge

A **negative electric charge** is an electric charge which is of the same sign as the electric charge on an electron.

When it is necessary to assign a value to a **negative electric charge**, a $-$ (minus) sign is used, and the value assigned is a negative number.

## Neutral

A body which has no **electric charge** on it is described as **(electrically) neutral**.

## Sources

- 1921: C.E. Weatherburn:
*Elementary Vector Analysis*... (previous) ... (next): Chapter $\text I$. Addition and Subtraction of Vectors. Centroids: Definitions: $1$. Scalar and vector quantities - 1951: B. Hague:
*An Introduction to Vector Analysis*(5th ed.) ... (previous) ... (next): Chapter $\text I$: Definitions. Elements of Vector Algebra: $1$. Scalar and Vector Quantities - 1960: M.B. Glauert:
*Principles of Dynamics*... (previous) ... (next): Chapter $1$: Vector Algebra: $1.1$ Definition of a Vector - 1990: I.S. Grant and W.R. Phillips:
*Electromagnetism*(2nd ed.) ... (previous) ... (next): Chapter $1$: Force and energy in electrostatics: $1.1$ Electric Charge