Electricity — OCR GCSE Physics
In summary: Electricity is a key topic in OCR GCSE Physics. Key exam tip: Always remember that only electrons move in static electricity scenarios.
Exam Tips for Electricity
- Always remember that only electrons move in static electricity scenarios.
- Ensure you can define current as the rate of flow of charge.
- Practice using the equation Q = I × t, ensuring units are in Coulombs, Amperes, and seconds.
- Always draw circuit diagrams with a ruler and use standard symbols.
- Remember that current is the same at all points in a series circuit.
- Remember that potential difference is the same across branches in a parallel circuit.
- Check if the component is ohmic (linear) or non-ohmic (non-linear) before applying V=IR.
- Show all working in calculations, including the formula used and the units in the final answer.
Common Mistakes
- Confusing insulators and conductors.
- Incorrectly assuming positive charge moves to make a material positive (it is the movement of electrons).
- Misunderstanding that static charge only builds up on insulators.
- Confusing the roles and connection methods of ammeters and voltmeters.
- Misunderstanding the behavior of current and potential difference in series versus parallel circuits.
- Difficulty grasping the concept of potential difference as energy transfer per unit charge.
Marking Points
- Charge is a fundamental property of matter with two types: positive and negative.
- Static electricity is produced by rubbing surfaces, leading to electron transfer.
- Charged objects exert forces of attraction or repulsion without contact.
- Static charge builds up only on insulators.
- Electric fields explain static electricity phenomena.
- Current is the rate of flow of charge (electrons).
- Conditions for charge flow: potential difference and a closed circuit.
- Current is constant at any point in a single closed loop.
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