• The First law of thermodynamics is same as law of conservation of energy.
• According to law of energy conservation: - Energy can neither be created nor be destroyed, only transformed to other forms.
• According to first law of thermodynamics:- The change in the internal energy of a closed system is equal to the amount of heat supplied to the system, minus the amount of work done by the system on its surroundings.

Mathematically:-

                 ΔQ = ΔU + ΔW

Where:

• ΔQ is the heat supplied to the system by the surroundings
• ΔW is the work done by the system by the surroundings
• ΔU is the change in internal energy of the system

Some of the inferences from the First law of thermodynamics are

1. There cannot be any device where we could get work done without any heat as input
2. Energy of universe or any isolated system is a constant
3. Like work, heat is also always conserved