First law of thermodynamics
What First law of thermodynamics means in Physics A-Level, as defined for AQA.
Definitions of First law of thermodynamics
Exam boards and our study guides word this term in slightly different ways. Learn the version your board uses.
Check what you remember
Read the wording for your board, then hide it and explain First law of thermodynamics in your own words. Rough notes are fine. This is a self-check, with no mark or grade.
Reference: AQA
A statement of conservation of energy for a system, linking internal energy change to heating and work.
Energy conservation for a thermodynamic system, written as Q = ∆U + W.
Topics that use First law of thermodynamics
- First law of thermodynamics (A-level only) (AQA A-Level)
- Thermal energy transfer (A-level only) (AQA A-Level)
Related terms
- Change of state
- Conservation of energy
- Energy transfer by heating and work
- Ideal gas
- Internal energy
- Internal energy changes in gases
- Mass flow rate
- Power
Using First law of thermodynamics in the exam
Check the command word and mark scheme for your exact question. After comparing your explanation with the reference, use the term in an answer on the linked topic. This practice does not predict an exam mark.
Practise Physics questions
Create a free account to answer exam-style questions on this topic and get feedback on your answers.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge