AQA AS Physics Electric Current

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Electric Current
- Component and their characteristics
- Potential difference and Power
  - Electrical power and Current
    - Work done = QV = (I?t) V = IV ?t
    - P = IV
  - Energy and Potential differece
    - Potential Difference is defined as the work done (or energy transferred) per unit charge.
      - V = W / Q
    - The mf of a source of electricity is defined as the electrical energy produced per unit charge passing through the source.
- Resistance
  - Ohm's law
    - It states that the pd across a metallic conductor is proportional to the current through it, provided that the physical conditions to not change.
  - Resitivity
    - ? = RA / L
  - Resistance
    - The resistance of any component is defined as: the pd across the component / the current trough it.
      - R = V / I
  - Superconductors
    - A superconductor is a wire ot a device made of material that has zero resistivity at and below a critical temprature that depends on the material.
- Current and Charge
  - ?Q = I?t
  - I = ?Q/?t
Work done = QV = (I?t) V = IV ?t
Resistance
- The resistance of any component is defined as: the pd across the component / the current trough it.
  - R = V / I

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