# Electric Field

🡑 Electrostatics

All charged particles generate electric fields which cause other charged particles to experience a electrostatic force. Mathematically an electric field is represented by a vector space.

Field lines point away from positive charges and towards negative charges. The further away from the charged particles, the weaker the electric field become.

Electric field also interact with each other. Here we have electric fields with two opposite charges. Field lines point away from the positive charge and go towards the negative charge.

In the next case, there are two positive charges. All field lines point away the positive charges.

If the both charges were negative instead, the field lines would look the same but the arrows would point in the towards the charged particles.

## Definition

If a positively charged particle was placed along a field line, it would experience an electrostatic force in the same direction as the arrow.

Conversely, if a negatively charged particle was placed along a field line, it would experience an electrostatic force in the opposite direction of the arrow. How will charged particle q2 interact with the field lines generated by charged particle q1? 

Recall that Coulomb’s law determines the amount of electrostatic force and direction (attraction or repulsion) a charged particle will experience from another charged particle.

\begin{aligned} F=k_e\frac{q_1q_2}{r^2} \end{aligned}

Electric field determines the direction and electrostatic force per Coulomb of charged particle.

\begin{aligned} \vec{E}=\frac{\vec{F}}{q_2}=k_e\frac{q_1}{r^2}\hat{r} \end{aligned}

Where:

\vec{E} = the electric field generated by q_1 in newton/coulomb

\hat{r} = the unit vector from q_1 to q_2

## References

 By User:Mfrosz – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1044851

 By E_FieldOnePointCharge.svg: User:Mfroszderivative work: Jfmelero (talk) – E_FieldOnePointCharge.svg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=5862992

 By Geek3 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10508433

 By Geek3 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10508472

 By Geek3 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10508514

 Modified to label q1, q2, and r – By Geek3 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10506218