Static Electricity
Understand Static Electricity for GCSE Physics with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. A separate (triple) physics topic: when insulators are rubbed together, electrons are transferred, leaving the objects positively or negatively charged.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
When certain insulating materials are rubbed together, electrons are transferred from one to the other. This is a Triple-only topic.
The material that gains electrons becomes negatively charged, and the one that loses electrons is left with an equal positive charge. It is always electrons that move — the positive charges in the nuclei do not.
Two charged objects exert a force on each other without touching. Like charges repel and unlike charges attract, and this is a non-contact force. When charge builds up sufficiently, it can cause a spark as electrons jump across the gap to earth.
Revision notes
How static charge builds up
When insulating materials are rubbed together, electrons are rubbed off one and onto the other.
The material gaining electrons becomes negatively charged. The material losing them is left with an equal positive charge. Only electrons move — the positive nuclei stay put.
Forces between charges
Like charges repel; unlike charges attract.
This is a non-contact force, acting without the objects touching. The closer the objects, the stronger the force.
Sparking
As charge builds up on an object, the potential difference between it and any earthed conductor increases.
If it becomes large enough, electrons jump across the gap, ionising the air and producing a spark. This is why charged objects can give a shock when touched.
Key points
- Rubbing insulators transfers electrons.
- The material gaining electrons becomes negative.
- The material losing electrons becomes positive.
- Only electrons move, never the nuclei.
- Like charges repel and unlike charges attract.
- A large charge build-up can cause a spark.
Worked examples
Example 1
A polythene rod is rubbed with a cloth and becomes negatively charged. Explain what has happened. [3 marks]
Model answer
Electrons have been transferred from the cloth to the polythene rod (1 mark). The rod has gained electrons so it has a negative charge (1 mark), and the cloth has lost electrons so it is left with an equal positive charge (1 mark).
Example 2
Explain why two positively charged objects move apart when brought close together. [2 marks]
Model answer
Like charges repel each other (1 mark), and this is a non-contact force acting between them without them touching (1 mark).
Example 3
Explain how a spark is produced by a charged object. [2 marks]
Model answer
As charge builds up, the potential difference between the object and an earthed conductor increases (1 mark). When it is large enough, electrons jump across the gap, ionising the air and producing a spark (1 mark).
Common mistakes
Saying protons move during charging.
Only electrons are transferred; the nuclei do not move.
Saying charge is created by rubbing.
Charge is transferred, not created — one object gains what the other loses.
Saying the force requires contact.
Electrostatic force is a non-contact force.
Forgetting the equal and opposite charge.
The two materials end up with equal and opposite charges.
Exam tips
- Always say electrons are transferred, never protons.
- State that the charges are equal and opposite.
- Use the term non-contact force.
- Remember this is a Triple-only topic.
Key terms
- Static electricity
- Charge that builds up on an insulator.
- Electron
- The negatively charged particle transferred by rubbing.
- Non-contact force
- A force acting without objects touching.
- Spark
- Electrons jumping across a gap, ionising the air.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.