How do you define the first law of thermodynamics?

The first law of thermodynamics states that energy can neither be created nor destroyed. The total amount of energy in the universe or in any dynamic system always remains constant. The law also states that energy can only be transformed from one form to another form.

The first law of thermodynamics is all about the law of conservation of energy. It also states that the internal energy of a system changes when heat energy flows into a system or out of it.

Thermodynamics deals with heat energy and entropy. Entropy and heat are interrelated, and entropy always increases in the universe. Entropy is the degree of disorder or chaos in the universe. There are four laws of thermodynamics.