Physics 12 · Physics · Lesson 6.1
Electric fields
- Level
- Grade 12
- Reading time
- 11 min reading
- Review
- Last reviewed 2026-09-03
- Standard
- Accuracy standard
- Errata
Abstract
Charges and forces.
What is an electric field?
Short answer
An electric field is the region around a charged object where it exerts a force on other charges. Its strength at a point is the force per unit positive charge, E = F/q, measured in newtons per coulomb. Field lines point away from positive charges and toward negative ones, and their density shows the field’s strength.
Concept preview
What you will be able to do
- 01Apply Coulomb's law for the force between charges
- 02Define and calculate the electric field of a point charge
- 03Relate field, force, and the motion of a charge
Matter carries electric charge in two varieties, positive and negative, measured in coulombs (C). The rule is famous: like charges repel, opposite charges attract. Charge is quantised — it comes in whole multiples of the elementary charge — and it is conserved: it can be moved around but never created or destroyed. Rubbing a balloon simply transfers electrons; it doesn't make new charge.
School Plan
Electric fields
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Related topics
Frequently asked questions
- Which way do electric field lines point?
- Away from positive charges and toward negative charges — the direction of the force on a positive test charge.
- What does the spacing of field lines show?
- Closer lines mean a stronger field; wider spacing means a weaker field.