Define one Coulomb charge.

Hint: Coulomb is the SI unit of electric charge. The electrostatic force between the two charges can be determined by Coulomb's law. So, the unit of electric charge is named after French physicist Charles Augustine de Coulomb.

Complete step-by-step answer:
In international standards, the unit of electric charge is Coulomb. This is named after the French physicist Charles Augustine de Coulomb. He was known for his discovery of Coulomb’s law in the electrostatics force. He also worked on the important concept of friction. In 1908, SI unit of electric charge was named in his honor.
Coulomb’s law gives the expression for the electric force acting on the stationary charges. According to the Coulomb’s law, the electric force between two stationary charges is
Directly proportional to the product of the charges
Inversely proportional to the square of the distance.
Thus, the expression of the electric force is:
$\Rightarrow F=\dfrac{k{{q}_{1}}{{q}_{2}}}{{{r}^{2}}}$
Where,
$\Rightarrow k=\dfrac{1}{4\pi {{\varepsilon }_{0}}}=9\times {{10}^{9}}\ \text{N}{{\text{m}}^{\text{2}}}{{\text{C}}^{\text{-2}}}$
${{q}_{1}}\ \text{and}\ {{q}_{2}}$ are the two charges
r is the distance between the charges
The electric charge is defined as physical properties of matter which causes the matter to experience force in an electromagnetic field is known as the electric charge.
One coulomb is the electric charge required to transport one ampere of current for one second. Thus, one electric charge is given by,
$\text{1}\,\text{Coulomb}\,\text{=}\,\text{1Ampere }\!\!\times\!\!\text{ 1second}$

Note: Alternate method
Current is given by,
$\begin{align}
  & \Rightarrow \text{Current=}\dfrac{\text{Charge}}{\text{Time}} \\
 & \Rightarrow \text{Charge=Current }\!\!\times\!\!\text{ time} \\
 & \Rightarrow \text{1}\ \text{C=1A}\times \text{1s} \\
\end{align}$