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.

It has been discovered by experiment that the corresponding force depends on the magnitudes of those electric charges, their displacements from each other, and their velocities.

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.

Symbol

The usual symbol used to denote the electric charge on a body is $q$.

Dimension

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

Units

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

The CGS unit of electric charge is the electrostatic unit $\mathrm {e.s.u.}$

Polarity

The polarity 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 polarity 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 polarity 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.

Also see

• Results about electric charge can be found here.