Electric Field Lines

Beginner

Visualize electric fields created by point charges using field lines and vectors.

Electric Field Theory

An electric field is a region around a charged particle where other charges experience a force. The field is represented by field lines that point in the direction a positive test charge would move.

Coulomb's Law:

E = k × q / r²

E = Electric field magnitude (N/C)

k = Coulomb's constant ≈ 8.99 × 10⁹ N⋅m²/C²

q = Source charge (C)

r = Distance from charge (m)

Field Line Properties:

  • Field lines originate from positive charges and terminate at negative charges
  • The density of lines indicates field strength
  • Field lines never cross each other
  • Lines are perpendicular to the surface of conductors

Interactive Simulation

Controls
Add Charge
Display Options

💡 How to Use:

  • Add positive (+) or negative (−) charges to the canvas
  • Click on charges to select them, then remove if desired
  • Toggle field lines to see electric field direction
  • Toggle vectors to see field strength and direction at grid points
  • Field lines point away from + charges and toward − charges
Current Charges (2)
Charge 1+1
Position: (200, 250)
Charge 2−1
Position: (400, 250)

Key Concepts

Superposition Principle:

The total electric field from multiple charges is the vector sum of individual fields. Each charge contributes independently to the total field at any point.

Field Direction:

The electric field points away from positive charges and toward negative charges. This is the direction of force on a positive test charge.

Inverse Square Law:

Electric field strength decreases with the square of distance. Doubling the distance reduces the field to 1/4 of its original strength.

Common Configurations:

  • Single charge: Radial field lines (spherical symmetry)
  • Dipole: +/- charges create characteristic curved pattern
  • Like charges: Field lines repel from each other
  • Opposite charges: Field lines connect the charges

Real-World Applications

Capacitors

Energy storage devices using electric fields between charged plates

Particle Accelerators

Use strong electric fields to accelerate charged particles

Lightning

Natural discharge when electric field exceeds air's breakdown limit

Electrostatic Precipitators

Remove particles from air using electric fields in pollution control

Discussion

Have questions or want to discuss electric fields? Join the conversation below.

Back to Electromagnetism