Electric Field Calculator - Coulomb's Law

This physics calculator helps you calculate the electric field strength due to a point charge using Coulomb's law. The electric field describes the force per unit charge experienced by a test charge.

Electric Field Definition

• Electric Field: Force per unit charge experienced by a test charge
• Formula: E = kQ/r² (Electric Field = Coulomb's constant × Charge ÷ Distance²)
• Vector: Electric field has both magnitude and direction
• Units: N/C (Newtons per Coulomb) or V/m (Volts per meter)

Electric Field Units

• N/C: Newtons per Coulomb (force per charge)
• V/m: Volts per meter (potential gradient)
• kV/m: Kilovolts per meter
• MV/m: Megavolts per meter

Coulomb's Law

• Force: F = kQ₁Q₂/r² (Force between two charges)
• Field: E = F/Q = kQ/r² (Field due to one charge)
• Constant: k = 8.99×10⁹ N⋅m²/C² (Coulomb's constant)
• Direction: Away from positive, toward negative charges

Applications

• Electrostatics: Charge interactions and forces
• Capacitors: Electric field between plates
• Particle Accelerators: Charged particle motion
• Atmospheric Physics: Lightning and thunderstorms
• Electronics: Circuit design and analysis
• Medical Physics: Electrocardiography and imaging

Electric Field Properties

• Superposition: Total field is sum of individual fields
• Conservative: Work done is path-independent
• Gauss's Law: Flux through closed surface ∝ enclosed charge
• Field Lines: Visual representation of field direction

Important Notes

• Electric field is a vector quantity
• Field strength decreases with distance squared
• Positive charges create outward fields
• Negative charges create inward fields
• Field is strongest near the charge

Electric Field Examples

• Point Charge: E = kQ/r² (radial field)
• Parallel Plates: E = V/d (uniform field)
• Dipole: E = kp/r³ (p = dipole moment)
• Line Charge: E = 2kλ/r (λ = charge per length)

Electric Field Effects

• Force on Charges: F = qE (force = charge × field)
• Potential Energy: U = qV (energy = charge × potential)
• Motion: Charged particles accelerate in electric fields
• Polarization: Electric fields can polarize materials

Safety Considerations

• High Fields: Can cause electrical breakdown
• Human Safety: Fields above 5 kV/m may be harmful
• Equipment: Electronic devices sensitive to fields
• Shielding: Conductive materials can shield fields