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IB Physics - Fields D.2 and D.3

IB Physics electric fields

Electric-field questions test three connected languages: vectors for field and force, scalars for potential and energy, and kinematics for charged-particle motion. Keep those languages distinct, then use the links between them deliberately.

Framework
IB Diploma Programme Physics
Level
IB Diploma Physics SL and HL
Guide format
Concept and practice pathway

Start with the model

Separate the vector map from the energy map.

Electric field strength describes force per unit positive test charge, so its direction is the direction a positive charge would accelerate. Electric potential is energy per unit charge and is scalar. A negative charge reverses the force direction relative to the field, while the sign of its potential energy follows the product of charge and potential.

Superposition also changes language: add electric fields as vectors, but add potentials as signed scalars. For parallel plates, a nearly uniform field supports constant-acceleration reasoning. For point charges, inverse-square field strength and inverse-distance potential require different distance dependencies and different graph shapes.

Study pathway

Four decisions that organize the topic.

Follow the sequence or open the step that matches your current gap. Destination pages keep their existing access rules.

  1. 01

    Read the field map

    Use field lines to encode direction and relative strength without treating them as particle paths.

    Open this step
  2. 02

    Calculate field and force

    Distinguish source charge, test charge, electric field strength, and the force on a particular charge.

    Open this step
  3. 03

    Superpose sources

    Resolve vector fields, preserve signs, and test candidate null points against the geometry.

    Open this step
  4. 04

    Connect potential and motion

    Use energy changes and uniform-field kinematics without mixing vector and scalar quantities.

    Open this step

Use it deliberately

A field-question decision tree

Before calculating, identify the quantity the question actually asks for and the geometry that determines its combination rule.

  1. 01

    Sketch the source positions and mark a positive coordinate direction or a radial direction.

  2. 02

    Decide whether each quantity is vector or scalar before adding contributions.

  3. 03

    For work or speed, consider potential energy; for acceleration or equilibrium, consider force and field.

  4. 04

    Check signs, distance dependence, symmetry, and whether a far-away or zero-separation limit makes sense.

Continue on GioPhysics

A mapped route, not a search-results wall.

Curriculum context on this page is public. Lessons, presentations, files, and practice follow the access message shown when you open them.

MapIB fields directorySee D.2 and D.3 concepts with their level labels and mapped routes.VisualizeElectric field linesInterpret field direction, density, and symmetry.CombineSuperposition and null pointsAdd field contributions with direction and geometry intact.EnergizePoint-charge potentialConnect potential, potential energy, and work.PractiseElectric-field applicationsSolve graduated field, force, and motion problems.

Questions before you begin

Clear scope, honest expectations.

What is the fastest way to distinguish electric field from potential?

Electric field is a vector linked to force per unit charge. Electric potential is a scalar linked to energy per unit charge. Ask whether the problem needs direction or energy.

Why does a negative charge accelerate opposite to the field?

The field direction is defined using a positive test charge. Since force equals charge times field, a negative charge reverses that direction.

Which parts are SL and which are HL?

The GioPhysics IB fields directory shows the current level label beside each mapped syllabus topic. Use that label and your school's current course guide rather than inferring level from this overview.