Point Charges
x (m)
y (m)
q (nC)
On
Visualization Mode
Query Point
x (m)
y (m)
—
|E| at query [V/m]
—
E direction [°]
—
V at query [V]
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F₁₂ Coulomb [N]
Theory
Coulomb's law (force between point charges):
$$F = k\frac{q_1 q_2}{r^2}, \quad k = 8.99\times10^9 \ \text{N·m}^2/\text{C}^2$$Electric field and potential (point charge q at distance r):
$$E = k\frac{q}{r^2}, \quad V = k\frac{q}{r}$$Superposition: $\mathbf{E}_{total} = \sum_i \mathbf{E}_i$, $V_{total} = \sum_i V_i$
Electrostatic energy (two charges): $U = k\dfrac{q_1 q_2}{r}$
Engineering applications: Capacitor field distribution / Charged-particle optics (mass spectrometers, electron guns) / EMC field concentration visualization / FEM boundary-condition hand-check (COMSOL etc.).