First Law Of Thermodynamics
Definition: The first low of thermodynamics is the application of the conservation of energy. Energy is neither be create or not be destroyed. The total amount of energy of the earth is a constant. The energy can be transferred from one form to another form.
The 1st law of thermodynamics can be mathematically stated as follows:
§dQ = §dW
In Thermodynamic Cycle, a cyclic process the systems undergoes, the cyclic integral of heat added is equal to integral of work done. The first law equation can be written in the form,
§(dQ – dW) = 0
First Law Of Thermodynamics Equation
Equation dU = dQ – dW is a corollary to the first law of thermodynamics. It shows that there exists a property internal energy (U) of the system, such that a change in its value is equal to the difference in heat entering and work leaving the system.
The sign convention for heat and work in the first law of thermodynamics is represented in the picture below.