**Fourier’s law of conduction**

**Rate of heat transfer by conduction along a given direction is directly poportional to the area of the heat transfer lying perpendicular to the direction of heat transfer.**

##### In the above expression, -ve sign denotes that** as x↑ T↓**

**“Heat always flows in direction of downhill of temperature.”**

**k is thermal conductivity**. It is thermophysical property of material slab