Key Concepts: Electric Field & Potential

Electric Field

• A region where a charged particle experiences a force. E = F/q = kQ/r².
• Direction: away from positive charges, toward negative charges.
• Unit: N/C or V/m.

Electric Potential (Voltage)

• Electric potential is the energy per unit charge: V = U/q = kQ/r.
• Potential difference (voltage): ΔV = W/q — work done per unit charge moving between two points.
• Unit: Volt (V). 1 V = 1 J/C.

Equipotential Lines

• Lines connecting points of equal potential. Always perpendicular to field lines.
• No work is done moving a charge along an equipotential.

Relationship: E = −dV/dr. The field points in the direction of decreasing potential.