# Physics: principles

## Introduction

The electrical and thermal phenomena in the electrical devices are described by different equations: Maxwell's equations, heat equation and material constitutive laws.

The simultaneous numerical solution of these equations is difficult to achieve because of the complexity and of the volume of computations to be carried out. For this reason, Flux software is provided with several physical applications, each one allows the solving of a given type of problem.

This chapter introduces the concept of physical application and treats the principles of modeling common to different applications.