First Law of Thermodynamics

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The First Law of Thermodynamics

If we are interested in how heat transfer is converted into doing work, then the conservation of energy principle is important.

Illustrative background for Calculation Illustrative background for Calculation  ?? "content


  • The equation for the first law of thermodynamics is:
    • The change in internal energy = the net heat transfer into the system - the net work done by the system.
    • ΔU=QW{\Delta}U=Q-W
  • Where U is the internal energy, Q is the heat and W is the work done by the gas.
Illustrative background for Work done Illustrative background for Work done  ?? "content

Work done

  • If the work is done by the gas the work done is positive, this is when a gas expands.
  • If the work done is on the gas the work done is negative, this is when a gas is compressed.
  • If the volume does not change there is no work done.

Jump to other topics

1Measurements & Errors

2Particles & Radiation


4Mechanics & Materials


6Further Mechanics & Thermal Physics (A2 only)

7Fields & Their Consequences (A2 only)

8Nuclear Physics (A2 only)

9Option: Astrophysics (A2 only)

10Option: Medical Physics (A2 only)

11Option: Engineering Physics (A2 only)

12Option: Turning Points in Physics (A2 only)

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