# 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 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