Question

SI unit electric field and electric force are ?

Answer 1

Hint: First of all, we have to understand electric field and electric force. The repulsive or attractive forces which act between two charges at a distance is known as electric force. Electric field is defined as a field in space where a charge exerts in force which is felt upon that particular area.

Complete answer:
Electric Force: In 1785 Charles Coulomb experimentally established the fundamental law of electric force between two stationary charged particles. He observed that an electric force between two charge particles share the following properties:

1. It is directed along a line joining the two particles and is inversely proportional to the square of the separation distance $r$, between them.
2. It is proportional to the product of the magnitudes of the charges, $\left| {{q_1}} \right|$ and $\left| {{q_2}} \right|$ of the two particles.
3. It is attractive if the charges are of opposite sign and repulsive if the charges have the same sign.

From these observations, Coulomb proposed the following mathematical form for the electric force between two charges. The magnitude of the electric force $F$ between charges ${q_1}$ and ${q_2}$ separated by a distance $r$ is given by,
$F = k\dfrac{{{q_1}{q_2}}}{{{r^2}}}$
where $k = \dfrac{1}{{4\pi {\varepsilon _0}}}$ also known as Coulomb constant.
The SI unit of electric force is Newton (N). The SI unit of force is always Newton.

Electric Field: A charge produces something known as an electric field in a space around it and this field exerts a force on another charge.Intensity of an electric field is the force acting on it on a unit positive charge.It can be expressed as,
$\overrightarrow E = \dfrac{{\overrightarrow F }}{q}$
Its Si unit is $\dfrac{N}{C}$ or can be said as Newton per Coulomb.

Note: It must be noted that the electric field of a charge has its own existence even if there is no other charge around itself. But this is not true for electric force. Electric force only acts when there is another charge around itself. There is a repulsive force for like charges whereas attractive force for unlike charges.