-- CALORIMETRY --
-- KINETIC THEORY --
-- 1st LAW OF THERMODYNAMICS --
-- 2nd LAW OF THERMODYNAMICS --
-- ELECTRIC FIELDS --
-- GAUSS'S LAW --
-- ELECTRIC POTENTIAL --
-- CAPACITORS --
-- DC CIRCUITS --
-- MIDTERM 1 - STUDY GUIDE --
-- MAGNETISM --
-- INDUCTION --
-- AC CIRCUITS --
-- ELECTROMAGNETIC WAVES --
-- OPTICS --
-- MIDTERM 2 - STUDY GUIDE --
-- INTERFERENCE & DIFFRACTION --
-- NUCLEAR PHYSICS --
-- QUANTUM PHYSICS --
-- FINAL - STUDY GUIDE --
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P19-040 – Principle of Superposition

Principle of superposition:

The net electric field at any point is equal to the vector sum of the respective electric fields that each charge distribution would create on its own.

\boxed{\overrightarrow{E}_{net}=\overrightarrow{E}_{1}+\overrightarrow{E}_{2}+\overrightarrow{E}_{3}+\dots}

Example:

The net electric field ${\overrightarrow{E}}_{net}$ at point $P$ is equal to the vector sum of the individual electric fields ${\overrightarrow{E}}_1$ and ${\overrightarrow{E}}_2$ created by point charges $q_1$ and $q_2$ respectively. Thus, we write

\boxed{{\overrightarrow{E}}_{net}={\overrightarrow{E}}_1+{\overrightarrow{E}}_2}

In practice, since the above equation is the sum of two vectors, we write it in component form as follows

\begin{aligned}
{\overrightarrow{E}}_{net}={\overrightarrow{E}}_1+{\overrightarrow{E}}_2\ \ \ \ &\Rightarrow \ \ \ \ \ \left\{ \begin{array}{c}
E_{net\ x}=E_{1x}+E_{2x} \\ 
E_{net\ y}=E_{1y}+E_{2y} \end{array}
\right. \\
\\
&\Rightarrow \ \ \ \ \ \left\{ \begin{array}{c}
E_{net\ x}=E_1{\mathrm{cos} \left({\theta }_1\right)\ }+E_2{\mathrm{cos} \left({\theta }_2\right)\ } \\ 
E_{net\ y}=E_1{\mathrm{sin} \left({\theta }_1\right)\ }-E_2{\mathrm{sin} \left({\theta }_2\right)\ } \end{array}
\right.
\end{aligned}

The magnitude of the net electric field at point $P$ is therefore equal to

E_{net}=\sqrt{E^2_{net\ x}+E^2_{net\ y}}=\sqrt{{\left(E_1{\mathrm{cos} \left({\theta }_1\right)\ }+E_2{\mathrm{cos} \left({\theta }_2\right)\ }\right)}^2+{\left(E_1{\mathrm{sin} \left({\theta }_1\right)\ }-E_2{\mathrm{sin} \left({\theta }_2\right)\ }\right)}^2}