BRAINCAKE

Electricity

OCR GCSE PhysicsTopic 3 of 820 lessons

Revision notes for Electricity in OCR Physics A (J249). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.

  1. Charge as a property of matterCharge is a property of all matter.
  2. Static electricity and sparkingStatic electricity is made when two surfaces are rubbed together.
  3. Electron transfer and static electricityOnly electrons move when an object becomes charged.
  4. Electric fieldsAn electric field is a region around a charged object where another charged object feels a force.
  5. Current and the conditions for charge flowCurrent is the rate of flow of charge.
  6. Current in a single closed loopIn a single closed loop, the current has the same value at any point.
  7. Charge, current and timeElectric current is the rate of flow of charge.
  8. Series and parallel circuitsIn a series circuit the components are connected one after another in a single loop.
  9. Circuit diagrams and symbolsA circuit diagram uses standard symbols so that anyone can read it and build the circuit.
  10. Current, potential difference and resistanceCurrent is the flow of charge and is measured in amperes (A).
  11. The equation V = I RThe current, potential difference and resistance of a component are linked by one equation: potential difference = current × resistance, or V = I R…
  12. Why resistance can changeIn a metal, current is a flow of electrons through a lattice of positive ions.
  13. Circuits to explore resistanceTo explore how a component behaves, connect it in series with an ammeter and a variable resistor, and connect a voltmeter in parallel with the…
  14. Linear and non-linear circuit elementsAn I-V characteristic is a graph of the current through a component against the potential difference (p.d.) across it.
  15. I-V graphs of wires, lamps, diodes and sensorsThe shape of an I-V graph depends on how the component behaves.
  16. Resistors in series and in parallelWhen two resistors are connected in series, there is only one path.
  17. Calculating in series and parallel circuitsUse potential difference = current × resistance (V = I × R) for the whole circuit or for any single component.
  18. Using circuits to measure and testSimple d.c. circuits are used to measure the properties of components.
  19. Power, p.d., current and energyThe power of a device is the rate at which it transfers energy.
  20. Circuit calculations: charge, resistance, power and energyCharge, current and time are linked by charge = current × time (Q = It).

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