Answer:
First law of thermodynamics.
Step-by-step explanation:
The first law of thermodynamics states that the change in internal energy of a system ΔE equals to the amount of heat energy supplied to the system H , minus the work done by the system on its surroundings. W.
The above definition can be expressed mathematically as: ΔE = H - W
This can also be restarted as energy of a close or isolated system is constant.