# Thermal Conductivity - heat flow rate

## Description

In physics, thermal conductivity (often denoted k, λ, or κ) is the property of a material to conduct heat. It is evaluated primarily in terms of Fourier’s Law for heat conduction.

Heat transfer occurs at a higher rate across materials of high thermal conductivity than across materials of low thermal conductivity. Correspondingly materials of high thermal conductivity are widely used in heat sink applications and materials of low thermal conductivity are used as thermal insulation. Thermal conductivity of materials is temperature dependent. The reciprocal of thermal conductivity is called thermal resistivity.

This equation is used for a one-dimensional case.

## Variables

Δ_{Q} | heat flow (joule) |

Δ_{t} | time (sec) |

k | conductivity (W/m*K) |

A | surface (m^{2}) |

Δ_{T} | temperature difference between the ends (K) |

Δ_{x} | distance between the ends (m) |