GCSE Physics revision

Electric fields

Static electricity (physics only)

AQA 4.2.5.2

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AQA student objectives

Learning pathway

ALL 🎯

Draw the electric field around an isolated charged sphere and use the field concept to explain non-contact forces and sparking.

MOST 🎯🎯

Apply the scientific explanation of electric fields to a relevant example.

SOME 🎯🎯🎯

Analyse a new situation involving electric fields and explain the scientific reasoning.

Revision summary

Read on screen, then print for Cornell-style active revision.

Every charged object has an electric field surrounding it, similar to how masses have gravitational fields and magnets have magnetic fields.
Electric fields are represented using field lines with arrows that always point from positive to negative charges.
Field lines must be drawn perpendicular (at right angles) to the surface of the charged object, and you should draw a good number of them (e.g. eight) in exam answers.

1. What is an Electric Field?AQA

Every charged object has an electric field surrounding it, similar to how masses have gravitational fields and magnets have magnetic fields.
Electric fields are represented using field lines with arrows that always point from positive to negative charges.
Field lines must be drawn perpendicular (at right angles) to the surface of the charged object, and you should draw a good number of them (e.g. eight) in exam answers.

The strength of an electric field is greatest closest to the charged particle and decreases with distance.
As charged particles move closer together, their electric fields begin to interact more strongly with one another.

Oppositely charged particles (one positive, one negative) experience an attractive force known as an electrostatic attraction.
This attraction is shown by field lines extending from the positive particle all the way to the negative particle, following the positive-to-negative rule.
Particles with the same charge (both positive or both negative) repel each other, following the rule that like charges repel.

3. Attraction and Repulsion Between ChargesAQA

Oppositely charged particles (one positive, one negative) experience an attractive force known as an electrostatic attraction.
This attraction is shown by field lines extending from the positive particle all the way to the negative particle, following the positive-to-negative rule.
Particles with the same charge (both positive or both negative) repel each other, following the rule that like charges repel.

Under normal conditions, air is an electrical insulator and cannot conduct electricity.
A very strong electric field around a highly charged object can cause surrounding air particles to lose electrons and become positive ions, in a process called ionisation.
Once air has been ionised, it becomes able to conduct electricity, which is how sparks are able to travel through the air between objects.

4. Ionisation of Air by Electric FieldsAQA

Under normal conditions, air is an electrical insulator and cannot conduct electricity.
A very strong electric field around a highly charged object can cause surrounding air particles to lose electrons and become positive ions, in a process called ionisation.
Once air has been ionised, it becomes able to conduct electricity, which is how sparks are able to travel through the air between objects.