Temperature Dependence of the Conductors' Resistivity

With increasing temperature in metal wires, the **amplitude of thermal motion** of the atom is increasing and thus leads to the growth of the **electrical resistivity**. The reasons for these changes in resistivity can be explained by considering the **flow of current through the material**. The flow of current is the **movement of electrons** from one atom (for example atom of Copper) to another under the influence of an **electric field**.



Some electrons are free to move in the structure of the matter. The current flowing in the material is therefore due to the movement of **free electrons**. The effect of heat on the **atomic structure** of a material is making the atoms to **vibrate**, and the higher the temperature the more violently the atoms **vibrate**.



The vibration of the atoms causes many collisions between the **free

electrons** and the **bound electrons**. Each collision uses up some energy from the free electron and is the basic cause of **resistivity**. The more the atoms jostle around in the material, the more collisions are caused and hence the greater the resistivity to the **electric current**.